We're planning way ahead, for our 20th anniversary in June 2019. We'll be travelling with our daughters, who will be 15 and 17 at the time. My husband has been to Spain in high school, the rest of us went to Europe for the first time for our 15th anniversary, when we went to London and Paris for a week each.
We'll have 2 weeks (could include weekends, so as many as 16 days) for travel, and it will be in early June. We like to travel on our own, but are open to doing a day tour in countries where we don't speak the language (DH speaks fairly fluent Spanish, we all speak a little French, and I'm learning German, but am in the extremely rudimentary stages). We enjoy castles, and cathedrals, museums (art- not really modern, but most others, science and natural history), enjoy outdoorsy/nature things (but are not extreme athletes). We enjoy cultural history, but are not big on military history. We're also into music, including classical music. The girls are probably more adventurous eaters than most of their peers, but they (along with DH) don't eat beef or pork, which I know can be limiting in some places.
So the places we've considered: Ireland, Scotland, Wales and the English countryside (could easily spend another day in London, but saw enough last time we'd be ok to miss it).
We've also considered doing more of central Europe. DH would enjoy Spain, although it has never been high on my must see list. We'd all enjoy France (central probably, to see chateaus and the countryside). I've always wanted to see Bavaria and the alps (although it's not on DH's must do list). I think we'd all enjoy Austria, and I've heard Prague is beautiful, although I had never considered it until the last couple years, so I don't know much about it. Italy is kind of second tier- we'd all enjoy it, but wouldn't set out just to go to Italy. Same thing with the Greek Isles.
So...what I'm looking for is guidance on what's feasible (if we go to Ireland, how easy is it to get over to England/Scotland/Wales, and how much of each could we do, or...if we do Central Europe, how many different stops is too much). Also, if anything I've said about us or our travel likes make you stop and say "Oh, you'd HATE x, don't go there, or you HAVE to go to Y" let me know. I tend to way over plan and have a hard time dialing back...