This probably isn’t helpful, but I like guided tours where a tour guide tells you about the castles and churches while everyone dutifully takes pictures to prove they were there. The guide/agency arranges the busses/boats and hotels so all you have to do is follow along with the program. The downside is that it always costs too much. The upside is that you spend less time waiting in lines because the planners will have all that worked out with the various sites. Some of those trips are almost exclusively senior citizens, but some have wider age ranges. Either way, you get to meet a set of fellow travelers who may become permanent online friends.