I highly recommend the Belizian island life. We stayed on Ambergris Caye which is beautiful and relaxed, and with great access to a lot of water adventures.
From there we took a bus down towards Belize City. We didn’t stay there though, as everyone told us to just skip it. Not much to see and do - just a quick change of bus, and then we went along the Western Hwy.
Accomendation is scares along the way but a lot of stuff to do and see along the Western Hwy towards Belmopan! Here you can go cave exploring, cave tubing, see Mayan ruins deep in the jungle and visit Belize zoo. Completely different experience than the island life, but highly recommendable none the less.
We felt perfectly safe every where we stayed. Just normal small hotels, nothing resort like, but there is some beautiful lodges in the jungle. We met people along the way who did home-stays and enjoyed it very much. Friendly and helpful people, also when you travel with public transport.
About 50 BZD one way from Corozal. It’s about two hours in a small “Thunderbolt” water taxi. Not exactly a pleasant trip, as you are seated in an small inside cabin, filled with luggage and people.
Busses was easy! There are bus terminals, and easy understandable schedules. We only met friendly and helpful people at ticket offices, and in the busses as well. But beware: the busses are old, most likely with no air con, and honestly looks like it’s retired American school busses. Luggage is stored down in the back of the bus, and not in a designated luggage compartment as you normally see in long distance busses. It’s easy, cheap, durable, but not luxurious.