Solution to a slightly different puzzle that takes 6 turns: Game #1618645

This empties the supply and also never trashes a card, so it ends up with an ending deck of the supply + 3 estates using TF/CH with a few extras; it has at least a 25% chance of working that fast.

Since reloading single player games doesn't seems to work very well so here is a log (the card-shaped things that actually matter are Counting House, Highway, Venture, Bank, Travelling Fair, and Banquet, with Baker for added consistency):

`t`

starts with 7 Coppers

and 3 Estates

.

t

shuffles their deck.

t

draws 4 Coppers

and an Estate

.

Turn 1 - tracer

t

plays 4 Coppers

.

t

buys a Banquet

and a Travelling Fair

.

t

gains 2 Coppers

and a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Copper

.

t

draws 3 Coppers

, an Estate

and a Counting House

.

Turn 2 - tracer

t

plays a Counting House

.

t

looks at 10 Governors

, 60 Coppers

, 5 Counting Houses

, 8 Oases

, 10 Butchers

, 10 Bands of Misfits

, 8 Duchies

, 10 Torturers

, 7 Estates

, 30 Golds

, 40 Silvers

, 10 Banks

, 7 Ventures

, 8 Provinces

, 10 Bakers

, 9 Highways

and 6 Curses

.

t

puts 7 Coppers

into their hand.

t

plays 10 Coppers

.

t

buys a Banquet

and 2 Travelling Fairs

.

t

gains a Copper

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

gains a Copper

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

gains a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Copper

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 3 Coppers

.

t

draws 3 Coppers

, an Estate

and a Counting House

.

Turn 3 - tracer

t

plays a Counting House

.

t

looks at 10 Governors

, 60 Coppers

, 5 Counting Houses

, 8 Oases

, 10 Butchers

, 10 Bands of Misfits

, 8 Duchies

, 10 Torturers

, 7 Estates

, 30 Golds

, 40 Silvers

, 10 Banks

, 7 Ventures

, 8 Provinces

, 10 Bakers

, 9 Highways

and 6 Curses

.

t

puts 13 Coppers

into their hand.

t

plays 16 Coppers

.

t

buys a Bank

and a Travelling Fair

.

t

gains a Bank

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

and 2 Travelling Fairs

.

t

gains a Copper

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

gains a Copper

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

gains a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Copper

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Copper

.

t

draws 3 Coppers

, a Bank

and a Counting House

.

Turn 4 - tracer

t

plays a Counting House

.

t

looks at 10 Governors

, 60 Coppers

, 5 Counting Houses

, 8 Oases

, 10 Butchers

, 10 Bands of Misfits

, 8 Duchies

, 10 Torturers

, 7 Estates

, 30 Golds

, 40 Silvers

, 10 Banks

, 7 Ventures

, 8 Provinces

, 10 Bakers

, 9 Highways

and 6 Curses

.

t

puts 17 Coppers

into their hand.

t

plays 20 Coppers

and a Bank

.

t

buys a Bank

and 5 Travelling Fairs

.

t

gains a Bank

.

t

reacts with a Travelling Fair

.

t

topdecks a Bank

.

t

buys and gains a Bank

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Bank

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Venture

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

draws 2 Banks

, a Counting House

, a Venture

and a Highway

.

Turn 5 - tracer

t

plays a Highway

.

t

draws a Bank

.

t

plays a Counting House

.

t

looks at 10 Governors

, 60 Coppers

, 5 Counting Houses

, 8 Oases

, 10 Butchers

, 10 Bands of Misfits

, 8 Duchies

, 10 Torturers

, 7 Estates

, 30 Golds

, 40 Silvers

, 10 Banks

, 7 Ventures

, 8 Provinces

, 10 Bakers

, 9 Highways

and 6 Curses

.

t

puts 26 Coppers

into their hand.

t

plays 26 Coppers

and a Venture

.

t

shuffles their deck.

t

reveals 3 Estates

and a Bank

.

t

discards 3 Estates

.

t

plays a Bank

.

t

plays 3 Banks

.

t

buys a Banquet

and 5 Travelling Fairs

.

t

gains 2 Coppers

and a Venture

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Venture

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Venture

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Venture

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

and 8 Travelling Fairs

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Highway

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys a Banquet

and 5 Travelling Fairs

.

t

gains 2 Coppers

and a Venture

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Venture

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Venture

.

t

buys a Banquet

.

t

gains 2 Coppers

and a Venture

.

t

buys a Banquet

.

t

gains a Venture

.

t

buys 7 Travelling Fairs

and a Curse

.

t

gains a Curse

.

t

buys and gains 4 Curses

.

t

buys 2 Travelling Fairs

and a Curse

.

t

gains a Curse

.

t

buys and gains 3 Curses

.

t

buys an Estate

and 4 Travelling Fairs

.

t

gains an Estate

.

t

buys and gains 3 Estates

.

t

buys an Estate

and 3 Travelling Fairs

.

t

gains an Estate

.

t

buys and gains 2 Estates

.

t

buys 2 Travelling Fairs

and an Oasis

.

t

gains an Oasis

.

t

buys and gains an Oasis

.

t

buys a Travelling Fair

and an Oasis

.

t

gains an Oasis

.

t

buys and gains a Band of Misfits

.

t

draws 5 Highways

.

Turn 6 - tracer

t

plays a Highway

.

t

draws a Highway

.

t

plays a Highway

.

t

draws a Highway

.

t

plays a Highway

.

t

draws a Highway

.

t

plays a Highway

.

t

draws a Counting House

.

t

plays a Highway

.

t

draws a Venture

.

t

plays a Highway

.

t

draws a Venture

.

t

plays a Highway

.

t

draws a Venture

.

t

plays a Highway

.

t

draws a Venture

.

t

plays a Counting House

.

t

looks at 10 Governors

, 60 Coppers

, 5 Counting Houses

, 8 Oases

, 10 Butchers

, 10 Bands of Misfits

, 8 Duchies

, 10 Torturers

, 7 Estates

, 30 Golds

, 40 Silvers

, 10 Banks

, 7 Ventures

, 8 Provinces

, 10 Bakers

, 9 Highways

and 6 Curses

.

t

puts 60 Coppers

into their hand.

t

plays 60 Coppers

and a Venture

.

t

reveals 3 Counting Houses

.

t

shuffles their deck.

t

reveals a Bank

.

t

discards 3 Counting Houses

.

t

plays a Bank

.

t

plays a Venture

.

t

reveals a Curse

and a Bank

.

t

discards a Curse

.

t

plays a Bank

.

t

plays a Venture

.

t

reveals a Venture

and an Oasis

.

t

discards an Oasis

.

t

plays a Venture

.

t

reveals a Bank

.

t

plays a Bank

.

t

plays a Venture

.

t

reveals a Curse

, an Estate

and a Venture

.

t

discards a Curse

and an Estate

.

t

plays a Venture

.

t

reveals a Curse

, an Estate

, a Counting House

and a Venture

.

t

discards a Curse

, an Estate

and a Counting House

.

t

plays a Venture

.

t

reveals 2 Curses

, 4 Estates

, a Bank

and a Band of Misfits

.

t

discards 2 Curses

, 4 Estates

and a Band of Misfits

.

t

plays a Bank

.

t

buys 165 Travelling Fairs

and a Province

.

t

gains a Province

.

t

buys and gains a Curse

, 40 Silvers

, 30 Golds

, an Estate

, 8 Duchies

, 7 Provinces

, a Counting House

, 7 Oases

, 9 Bands of Misfits

, 10 Bakers

and 10 Butchers

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains a Counting House

.

t

reacts with a Travelling Fair

.

t

topdecks a card

.

t

buys and gains 10 Torturers

, 6 Banks

, a Highway

and 10 Governors

.

t

draws 5 Counting Houses

.