I've heard great things about Costa Rica -- specifically the Dominical area. Never been, but headed there in about a month.
Dominical is about the most touristy beach town of all of Costa Rica. I would not reccomend it.
Well, to figure out where is best for you, it depends on how you plan to go about that lifestyle.. whether you plan to grow all or part of your own food, or buy it from those who do, or are fine with imported things. It depends on what type of socializing and community you are looking for, and recreation/entertainment you want/need, what type of budget you have or don't have, etc. Each area has its pros/cons in relation to these things for every choice. Kauai works for me more than most places.
I went to Costa Rica for four months and have to say it is not the fruit paradise one would expect. Almost everything is pesticide/herbicide saturated so much so it can be tasted.
Costa Rica seems to be trying to emulate American culture with loads of processed packaged food, cell phones, music, tv, bill boards.. which is quite sad.
I went down there with the thought of starting my own tropical farm someday. I worked on a couple of farms and it is sooo hot it is difficult to work.
However, if you are going to visit it's essential to find somewhere that has a good farmers market. San Isidro was the best place we found and actually had organic fruits and greens.
There's a couple farms around there but they both require pay as well as work. WWOOF is kind of turning into tourism down there.
I am now interested in southern Spain. I had no idea until recently that tropical fruit like bananas, cherimoyas, papayas can be grown there. There is a really amazing family I found that has a farm there and they do some volunteer exchanges I think. I hope to visit them someday!
By the way, where in Oregon are you from? I'm currently in Walla Walla, WA and recently attempted to move to Portland but found it waay to busy.