We have explained a little of our plan on other threads. The budget for our boat will be $30-60K. You are right, we are looking for the smallest boat we can find that meets our few requirements.
We need a boat with 2 separate sleeping areas, although a aft quarter berth might work. We just don't want to have to sleep in the dinette every night. It would also be nice if it had a separate shower too.
As far as the cost we are very frugal and know how to do most maintenance work ourselves. Of coarse we have no way of knowing the real cost until we get out there. That's why we plan to spend a few yrs in the USA learning what works and what doesn't. At this point we are not worried about the money, we'll have enough.