We have a good number of taxi vans that can carry big wheelchairs.Also our bus service will be able to put the larger electric wheel chairs in the back door of most buses. In reality they are not equipped but can find room and the Belize people are humble and respectful when it deals with folks in need as long as you are in need and humble yourself, I would think you could travel in the country on the bus. If you have enough patience to do it. So its a complete yes on Taxis, the Bus would be an adventure but I am sure they would work with you. I have the phone numbers of several taxis that could help if you want. My X husband was an electric wheelchair world traveler, we did Banf, Hawaii, Italy, Belize, Costa Rico, etc...sadly he passed 15 yr ago. The chairs where bigger then as well. Also no problem with the electric chair on any water taxi...come and enjoy..
To Debunk..we have a very lovely young woman that runs our Traffic Dept..on an electric wheelchair..She is very beautiful an shopping in the City and travels to Mexico she has no problems..