hey diann...
First of all, don't stay north because of the beaches... there are none. They clear a few feet of weed and tell eveyone they have a beach. How do I know? I use to work up north and I told them we had a great beach. Maybe growing up and going to Wildwood and Atlantic City has given me a false impression of what a beach is but....

I'd stay in town or just south of town... remember Belize isn't known for it's beaches at all, mainly because it has none. Known more for scuba and mayan ruins.