I think this is a very difficult board to analyze fwiw, mostly because of Bishop.
When figuring out what to open, you should ask yourself what your plan is. How are you winning with this deck? On a board with Chapel/Bishop, you should be aware of the strategy of trashing down to a 5 card deck consisting of Bishop, Gold, Gold, Silver, Province. Each turn, you trash the Province for 5 VP, then buy another Province. This is often a strong strategy, and the first one you should consider on Chapel/Bishop boards. Here, there's a good counter against that deck though, Militia. If you go for the 5 card deck, and your opponent goes for a deck which can play Militia every turn, you're probably losing. Your counter strategy against a deck which plays Militia every turn might be a 5 card deck consisting of Bishop, Gold, Gold, Market, Market. This gets you a guaranteed $6 every turn after trashing a Gold, so you can buy a new Gold, and repeat the cycle with a 4 VP gain every turn. However, this deck can not end the game, since it doesn't buy Provinces. Is 4 VP every turn enough to beat a Militia-every-turn deck? Well, probably not against a perfect opponent.
If you were to go for the above 5 card deck, your opponent could set up a 10 Market/10 Throne Room type deck which probably has a much stronger end game than the 4 VP a turn deck. It could use Workshop to quickly gain cards to trash to Bishop(s), probably winning the end game pretty comfortably as far as I can tell. It could of course also buy Provinces to end the game if it was necessary. Plus, you know, play a Militia every turn. I don't see how any 5 card deck beats it, and a weaker "normal" deck aiming to buy Provinces will probably lose to a huge Rabble chain in the end game (say the deck aiming for Provinces buys 4 Provinces. Now the opponent plays 10 Rabbles a turn while setting up a Bishop win. I'm guessing this is doable, while the Province player is semi locked. There's also Thief which may or may not come into play at that stage of the game).
The best counter I can see against a big Throne Room/Market/x/y/z engine is to go for it myself. Maybe I'm wrong, I suck at this type of board.
Now that we know what our strategy is, we can go back to the opening and early game. Opening Chapel is a given. Opening Militia is probably necessary too; hitting the opponent on his Chapel turn is super huge and might come close to deciding the game on the spot, and denying us the chance of having that happening seems risky. After that, we really want to get to $5 to get a Market, and then Throne Rooms. It's tough to say exactly when and in what order etc, it will depend too much on what happens with the Militias and Chapels in both decks. Picking up a Workhop at the right moment might be what wins you the Throne Room split, too.
