Any ideas on how to make the best use of this time?

Hi everyone - my husband and I are just beginning our research to look for a new beginning for our retirement.  Belize is at the top of the list - as well as Ecuador and possibly Costa Rica. 
We are currently planning on splitting our time - Jan thru May (possibly June) in Belize and the rest of the time RV-ing across America for about 4 to 5 years.
At that time we will decide on a permanent place of residence.

I will continue to read and learn as much as possible from what I read on this forum.

we are planning on our first visit this February and can stay for about 3 weeks.  Any ideas on how to make the best use of this time?

rent a small SUV and drive around.   look at everything, go to the expat bars & resturants and ask a zillion open ended questions.   each person will have a different view of resources and issues here in Belize.   Notice the difference in climate and topography from place to place.   I live in the Corozal district.  The Cayo district is said to have the best climate.  Ambergris and Placencia are seen as tourist places.   check it out.    that said.  there is no way to know this country on the basis of a visit.  Come rent for a year and then you will know.

mzcalifornia gave great advice.  3 weeks isn't enough time to see the  whole country.  I would do research on 1 or 2 of your top locations and concentrate on visiting them for your first short visit.  Then for your first 6 mo. stay you can  further explore the country.   If you try to explore the entire country in 3 weeks you really won't get a good feel for the areas you visit.  Take your time and visit Belize at different times of year before you decide to buy.
Belize is wonderful, but also has it's challenges so do your research.