Any of the "Sun" class ships (Sun, Dawn, Sea) would be your best bet in terms of size... they are 77,000 GRT, similar to the "Vision" class on RCI. I think they would also give you a good age mix, because they are considered the older ships now (even though they're only 6 years old) so they have a cadre of loyal followers that tend to be older, along with the younger people that they still attract. The newer Princess ships like the bigger "Grand" class tend to be more attractive to families, young people, and first-time cruisers, and less attractive to older more experienced cruisers.
As you know by now, the biggest drivers of age mix are length of cruise and sailing date... and Princess is no exception to that rule. Anything over seven days will drive the age up a bit, and 14 or over will drive it up quite a bit more. Anything when school is out will have lots of kids and families no matter how you slice it.
Princess will have all the activities you've mentioned. They are very strong on things like wine tastings and dance classes, and they have a great healthy choice menu. They have plenty of sports and fitness activities as well, although they don't have a prominent program like "ShipShape". You can stay pretty active in the gym and in classes that they offer... you just have to look for them a little harder on Princess.
The only place Princess may fall down for you is on the night life (I know there are people who will disagree, and hopefully some will reply to your post). Princess in general, but especially the "Sun" class and older ships are just not that lively in terms of "great live music and dancing" ...especially if you move away from sailings with a lot of young people.
I'm a loyal Princess passenger, and in your age group, but I'm just not that lively at night so it's great for me. I've also sailed RCI many times and thoroughly enjoyed every one of them as well.
Hope this helps... whatever you decide, have a great cruise!!
