Have a good time in Belize
When you head over towards Guatemala you may want to turn south and go to Hopkins on the Belize coast. It is a neat little coast town, lots of tiny places to stay. The ride south is really pretty compared to the flat dried out country around Cancun and northern Belize,lots of orange groves, limestone hills etc. Check out the Mennonite bakeries and cheese places. Too bad you must come out the way you went in but... The road into Guatemala is rough gravel (but I did it on a Harley bagger) then to Tikal. From there the road south in Guatemala towards Puerto Barrio is new pavement and great.
Its all good.