Liability insurance is mandatory, collision is optional.....it is pretty cheap though.
Tenncrusher- that sounds like an awsome trip...don't personally know anyone who has done it but it is not so expensive. Check out www.yucatanexpress.com. :D
HLTOPPER:
Great trip!!! I wish I could go with you...I am planning a trip for the same time...a ferry cruise from tampa to yucatan...going to see the ruins in mex, belize and guat....you will need...
Title for the truck
(if you are paying it off you'll need a letter from the bank)
Insurance...