Hey, this is a really cool idea! Real game puzzles in Dominion are a bit weird compared to Prismata because Prismata is a game of perfect information with no randomness beyond the setup, but playing around with the buy orders after using undos allowed me to solve both normal mode and hard mode within hour without hints.

My overall strategy:Well, I know how bonkers Bridge Troll is. If you have the opportunity to get four or more Bridge Trolls into play with ease, you just buy the extra Bridge Trolls you need to pile Provinces with minimal additional Villages. So I tried to make that happen. The challenge is balancing the trashing needed to get a bunch of Bridge Trolls into play at once, and actually finding a way to purchase the Bridge Trolls and support cards needed to get it all to come together in time.

What I learned:Well, it was interesting how in normal mode I could get away with trashing with Masquerade at every Masquerade play, but in hard mode I had to hold back on trashing all my Coppers with Chapel as early as Turn 5.

You can copy paste these into a text editor or something for convenient viewing, or just check the quote of this post.

Normal Mode: #11933577

Game #11933577, unrated.

m starts with 7 Coppers and 3 Estates.

m shuffles their deck.

m draws 3 Coppers and 2 Estates.

Turn 1 - markusin

m plays 3 Coppers.

m buys and gains a Masquerade.

m draws 4 Coppers and an Estate.

Turn 2 - markusin

m plays 4 Coppers.

m buys and gains a Masquerade.

m shuffles their deck.

m draws 2 Coppers, 2 Estates and a Masquerade.

Turn 3 - markusin

m plays a Masquerade.

m draws 2 Coppers.

m trashes an Estate.

m plays 4 Coppers.

m buys and gains a Poacher.

m draws 3 Coppers, an Estate and a Masquerade.

Turn 4 - markusin

m plays a Masquerade.

m shuffles their deck.

m draws 2 Coppers.

m trashes an Estate.

m plays 5 Coppers.

m buys and gains a Bridge Troll.

m draws 2 Coppers, an Estate, a Poacher and a Masquerade.

Turn 5 - markusin

m plays a Poacher.

m shuffles their deck.

m draws a Copper.

m plays a Masquerade.

m draws a Copper and a Bridge Troll.

m trashes an Estate.

m plays 4 Coppers.

m buys and gains a Village.

m shuffles their deck.

m draws 4 Coppers and a Masquerade.

Turn 6 - markusin

m plays a Masquerade.

m draws a Copper and a Village.

m trashes a Copper.

m plays 4 Coppers.

m buys and gains a Village.

m draws 2 Coppers, a Poacher, a Masquerade and a Bridge Troll.

Turn 7 - markusin

m plays a Poacher.

m shuffles their deck.

m draws a Copper.

m plays a Bridge Troll.

m plays 3 Coppers.

m buys and gains a Bridge Troll.

m draws 2 Coppers, 2 Villages and a Masquerade.

Turn 8 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m plays a Village.

m draws a Copper.

m plays a Village.

m shuffles their deck.

m draws a Copper.

m plays a Masquerade.

m draws a Poacher and a Masquerade.

m trashes a Copper.

m plays a Poacher.

m draws a Copper.

m plays a Masquerade.

m draws a Copper and a Bridge Troll.

m trashes a Copper.

m plays a Bridge Troll.

m plays 4 Coppers.

m buys and gains 2 Villages and a Bridge Troll.

m shuffles their deck.

m draws 3 Coppers, a Village and a Bridge Troll.

Turn 9 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m plays a Village.

m draws a Poacher.

m plays a Poacher.

m draws a Village.

m plays a Village.

m draws a Village.

m plays a Village.

m draws a Masquerade.

m plays a Masquerade.

m draws a Village and a Bridge Troll.

m trashes a Copper.

m plays a Village.

m draws a Copper.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays 3 Coppers.

m buys and gains 2 Villages and 2 Bridge Trolls.

m shuffles their deck.

m draws a Copper, 2 Villages, a Masquerade and a Bridge Troll.

Turn 10 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m gets +1 Buy (Bridge Troll).

m plays a Village.

m draws a Copper.

m plays a Village.

m draws a Copper.

m plays a Masquerade.

m draws a Village and a Masquerade.

m trashes a Copper.

m plays a Village.

m draws a Village.

m plays a Village.

m draws a Bridge Troll.

m plays a Masquerade.

m draws a Poacher and a Village.

m trashes a Copper.

m plays a Village.

m draws a Village.

m plays a Poacher.

m draws a Bridge Troll.

m plays a Village.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Copper.

m buys and gains 2 Villages, a Courtyard and 3 Bridge Trolls.

m shuffles their deck.

m draws a Poacher, a Village, a Courtyard and 2 Bridge Trolls.

Turn 11 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m gets +1 Buy (Bridge Troll).

m gets +1 Buy (Bridge Troll).

m plays a Village.

m draws a Bridge Troll.

m plays a Poacher.

m draws a Bridge Troll.

m plays a Courtyard.

m draws 3 Villages.

m topdecks a Bridge Troll.

m plays a Village.

m draws a Bridge Troll.

m plays a Village.

m draws a Copper.

m plays a Village.

m draws a Village.

m plays a Village.

m draws a Village.

m plays a Village.

m draws a Village.

m plays a Village.

m draws a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Copper.

m buys and gains a Duchy and 8 Provinces.

m shuffles their deck.

m draws a Province, a Village, 2 Masquerades and a Bridge Troll.

Hard Mode: #11933865

Game #11933865, unrated.

m starts with 7 Coppers and 3 Estates.

m shuffles their deck.

m draws 3 Coppers and 2 Estates.

Turn 1 - markusin

m plays 3 Coppers.

m buys and gains a Chapel.

m draws 4 Coppers and an Estate.

Turn 2 - markusin

m plays 4 Coppers.

m buys and gains a Poacher.

m shuffles their deck.

m draws 2 Coppers, 2 Estates and a Poacher.

Turn 3 - markusin

m plays a Poacher.

m draws a Copper.

m plays 3 Coppers.

m buys and gains a Poacher.

m draws 3 Coppers, an Estate and a Chapel.

Turn 4 - markusin

m plays a Chapel.

m trashes 3 Coppers and an Estate.

m shuffles their deck.

m draws 2 Coppers, an Estate and 2 Poachers.

Turn 5 - markusin

m plays a Poacher.

m draws an Estate.

m plays a Poacher.

m draws a Chapel.

m plays a Chapel.

m trashes a Copper and 2 Estates.

m plays a Copper.

m buys and gains a Village.

m shuffles their deck.

m draws 2 Coppers, 2 Poachers and a Village.

Turn 6 - markusin

m plays a Poacher.

m draws a Copper.

m plays a Poacher.

m draws a Chapel.

m plays a Village.

m plays 3 Coppers.

m buys and gains a Bridge Troll.

m shuffles their deck.

m draws a Copper, a Chapel, a Poacher, a Village and a Bridge Troll.

Turn 7 - markusin

m plays a Village.

m draws a Copper.

m plays a Poacher.

m draws a Copper.

m plays a Bridge Troll.

m plays 3 Coppers.

m buys and gains a Bridge Troll.

m shuffles their deck.

m draws 2 Coppers, 2 Poachers and a Bridge Troll.

Turn 8 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m plays a Poacher.

m draws a Village.

m plays a Poacher.

m draws a Copper.

m plays a Village.

m draws a Chapel.

m plays a Bridge Troll.

m plays a Chapel.

m trashes a Copper.

m plays 2 Coppers.

m buys and gains a Village, a Courtyard and a Bridge Troll.

m shuffles their deck.

m draws a Copper, a Chapel, 2 Poachers and a Courtyard.

Turn 9 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m plays a Poacher.

m draws a Bridge Troll.

m plays a Poacher.

m draws a Village.

m plays a Village.

m draws a Copper.

m plays a Courtyard.

m draws a Village and a Bridge Troll.

m topdecks a Copper.

m plays a Village.

m draws a Copper.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays 2 Coppers.

m buys and gains 2 Villages and 2 Bridge Trolls.

m shuffles their deck.

m draws 2 Coppers, a Village and 2 Bridge Trolls.

Turn 10 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m gets +1 Buy (Bridge Troll).

m plays a Village.

m draws a Poacher.

m plays a Poacher.

m draws a Courtyard.

m plays a Courtyard.

m draws a Poacher and 2 Villages.

m topdecks a Copper.

m plays a Poacher.

m draws a Copper.

m plays a Village.

m draws a Chapel.

m plays a Village.

m draws a Village.

m plays a Village.

m draws a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Chapel.

m trashes 2 Coppers.

m buys and gains 2 Villages, a Courtyard and 3 Bridge Trolls.

m shuffles their deck.

m draws a Poacher, 2 Villages, a Courtyard and a Bridge Troll.

Turn 11 - markusin

m starts their turn.

m gets +1 Buy (Bridge Troll).

m gets +1 Buy (Bridge Troll).

m gets +1 Buy (Bridge Troll).

m plays a Village.

m draws a Bridge Troll.

m plays a Village.

m draws a Village.

m plays a Poacher.

m draws a Chapel.

m plays a Village.

m draws a Village.

m plays a Village.

m draws a Bridge Troll.

m plays a Courtyard.

m draws a Village and 2 Bridge Trolls.

m topdecks a Chapel.

m plays a Village.

m draws a Chapel.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m plays a Bridge Troll.

m buys and gains a Duchy and 8 Provinces.

m shuffles their deck.

m draws a Province, a Poacher, 2 Villages and a Courtyard.

Edit: Figured out how to load old solitaire games. It doesn't work if you don't use the "Create Table" option and then edit the table to load old game in advanced options. Going directly to "Load Old Game" won't remember your min players = 1 setting.