I love Corozal Town and environs. It's untouristy, friendly, safe and cheap, and the Bay of Chetumala/Corzal is beautiful.
Having said that, there's not a whole lot to do or see. There are two *small* museums, a small Maya site near town (Santa Rita) and another site with a wonderful setting on the water across the bay (Cerros). To see much outside of town, you really need a car. It's an interesting day trip to Sarteneja and Shipstern. There are some cheap good restaurants such as Cafe Kela and Cactus and most of the lodging is under US$50 or $60.
You can fly to Corozal from San Pedro, but I don't know that I would do it just as a day trip. It's the kind of place where you need at least a couple of days to settle in.
--Lan Sluder www.belizefirst.com