Have traveled to AC since 1989 and have found no problem w/ travelers checks. Most of the hotels will gladly exchange them for you as needed. Most of the shops/restaraunts will take them. I have only ever used American Express checks, so do not know about other. It is good to also have some small denomination money also for tips on tours (which generally take travelers checks for payment also)and small purchases. Even though we have never had a problem, be safe and use the travelers checks for the bulk of your funds. Have fun and I hope that you get to see the rest of the country also.
Stephi G

Stephi G
Frequent Belize Traveler
Since 1989