Need help picking location for sister trip in 2027

My sister and I (54/48) have never travelled alone together, and we've been talking about it for a few years now. We've decided we'd like to do a 5-9 day trip in the US, Europe, Caribbean, or Central America. My sister hasn't travelled internationally very much, but I have. We have different preferences as well for what we enjoy while travelling. My husband and I often pick locations to go hiking and be more active. We also enjoy cities. My sister doesn't like hiking or big cities. We do both do enjoy good food. She is a vegetarian, so that plays into location as well.

I'd prefer not to travel again (with her) to Iceland, London, Paris, Amsterdam, Prague, Switzerland, Rome, Florence, Dolomites. She prefers warm/hot weather and enjoys some beach time. I'm ok with weather above 50 degrees but don't like super hot, and am generally no a huge beach goer, but will do a couple days. Neither of us wants a cruise. We are flexible on which month to travel, and will base it on best weather for wherever we decide on. Cost ideally under $5000/person. We'd be flying from DTW. We often visit San Francisco/Boston/Chicago based on our kids. US places we don't want include Florida, TN, most of south US, TX (I lived there).

My ideal place would be somewhere where we stay in one spot and take public transportation for day trips or to second locations. I have anxiety about driving in new places.

Some thoughts I had:

Costa Rica, Lisbon/Porto, Santa Fe, St. Thomas, Venice/Milan/Northern Italy

Would love any thoughts or ideas!