It was suggested we look into a "Castle/Heritage" pass for England and Scotland. We've done some research but I still can't decide if this is going to be worth the money. I don't see anything about these "passes" on Rick Steves website or in the books.
They can be a good value if you are going to enough of their properties on your visit. There is English Heritage, Historic Scotland, and various other passes like the Royal Palaces pass that my sister and I used while in London last year since the pass was cheaper than paying outright entrance fees to Kensington, the Tower of London etc... My husband and I have also become members of Historic Scotland for a year because we were again visiting enough properties that it was cheaper to be members than pay individual admission fees. Just check out each of their websites for how much a pass/membership is and how many of their properties you are visiting and at what cost. That will tell you which is the cheaper option.
Don’t forget that a lot of Manor Houses etc. are owned by the National Trust. In Wales, CADW runs most of the Castles. Then, many buildings are run privately.
Rick's summary of these passes is toward the back of the books in the "Practicalities" chapter (e.g., p. 858 in RS England, 8th Edition). These cover primarily houses, castles, and archeological sites. If traveling in winter, many of the covered heritage properties can be closed. You're less likely to use this type of pass in big cities like London and Edinburgh, where a good portion of your visit could be spent at National Museums that are free.
Rick did a good radio show about this:
Some of the other podcasts have info about gardens and they also give info about the stately homes that they are located near.