Where to go this summer? Open minded

Hi,

I'm unemployed and looking to take an awesome trip sometime this summer. Really really open to anything from 2 weeks from now till September. Length of trip anywhere from 4-14 nights. I would most likely be solo if traveling in May and June, but would be with my fiance if I go in July-August. Budget for flights around $500 for a weekish, $1200 for 2+ weeks (which is now not looking too great).

We/I have been all over - Japan, Mexico, Belize, Canada, western Europe, Costa Rica, Puerto Rico, Norway. I love both massive cities and nature. I was thinking about going to Vietnam and doing the Hai Giang loop but the weather looks too hot for me. I'm really just looking for an adventure.

We/I would be traveling from Boston - where would you like to go if you were in my position?