Hariette makes some good points.
Although coming for frequent visits gives you an idea of what to expect and what you might be up against, there is nothing that will prepare you better than being here for a long stretch. I would recommend no less than 3 months. Things happen pretty slow here, but that should give you enough time for most things that would irritate you to come to pass.
When you are here for visits...2 or 3 weeks at a time...you never get to comprehend the difficulties you will encounter by being here for extended periods. Those little enlightning tidbits come out of the blue one day when you want some insignificant thing...and you spend half the day looking for it all over town...and still go home empty handed. Sometimes it won't bug you...other days it will drive you nuts.
A good 6 months gives you an excellent grasp on what the rest of your life will be like in Paradise. Then you can adequately judge whether you can live here in complete peace...or whether it isn't your cup of tea.
Owning a business here brings a whole new set of obstacles to climb. Nothing is the same here in business except how to use your calculator....LOL
If you are looking to be a golf pro...well, I can't offer much in the way of advice. That is certainly not something we have a lot of.
Banking can be complicated and not always completely reliable. You will need to check and make sure your money is being handled and reported correctly. Don't pile your bank statements up on the corner of your desk...open them and reconcile them...immediately! LOL
Staff/Employees = Migrane headache
I'll say no more on this subject...LOL
There is a lot to be learned before considering a move here and especially before opening a business. I've learned the only way to really enjoy it here is to either be retired so you have a consistent income every month and can be comfortable...or to own a business so you are making the profits. Even then, being happy and comfortable owning a business is dependent on the type of business, being wise in your overhead expenses, location(location...location) and supply and demand(BELIZE supply and demand).
Hariette is also right about the "Belize Manual" LOL
Two pre-requisites for living here...you must read: "Don't Stop the Carnival" by Herman Wouk and
"Don't Sweat the Small Stuff" by Richard Carlson, PhD.
It helps if you hang out at BC's on Sundays and talk at length with the locals....they have all been there...and done that. LOL
With all that said...you should be in pretty good shape!
Cheers...and good luck!