The original cast of "The Last Sweet Days of Isaac" is a great cast album, and I think it is Cryer/Ford's best score. The song "Love You Came To Me" is among my favorite musical theater songs of all time. If you are a fan of musicals in the 1970s you should definitely get this one.
"Onward Victoria" is a campy delight with some sumptuous orchestrations. "Canterbury Tales" is not a priority in my opinion, but worth getting. You may want to hold off on "Make A Wish" as the Sepia issue is from 78s and you never know if Broadway Masterworks will reissue it using the master tapes. The sound is fine with Sepia, but it is not worth rushing.
I like "Dance A Little Closer," but don't listen to it much. It has been a while since I listened to "Robert and Elizabeth" but I remember the score being quite lovely.
"Christine" never grew on me but I've thought of giving it another chance.
Look at this weird Make A Wish item on ebay.
With Irma you gotta do something!