It might be possible to get extra forced decisions by gaining Border Village instead of Gold, forcing a gain of a lower cost card. Perhaps upgrade Catacombs into the last <5 cost, then force a Border Village gain of a 5 cost.
Also, is it a forced decision to gain nothing, if no eligible cards remain in the Supply? E.g. TR an Upgrade, trashing Catacombs, gaining a card w/ cost <5 (last Moat), gaining a 6 cost card(Border Village), gaining a card with cost <6(no cards left to gain)
If so, just gain a Border Village in place of each Gold in the solution(start with no Gold left of course), and you have 10 extra forced choices. You'll have to remove Moat and Wharf from the kingdom, to prevent a choice between them; just gain nothing when Upgrading Rats/Catacombs.