Forget the wetsuit - They act like an evaporative cooler when wet and the breeze is blowing. A drysuit packs down to the size of a grapefruit and can make a huge difference in how comfortable you are on your trip. Even if you never need to get it out, it's worth having. The drysuit's probably the most critical piece of personal gear (after a PFD) you can have for enjoying a trip down there during the shoulder seasons.
If you're rowing/riding a 14' boat, you'll want to wear it every day.
As for the jetboil, that's a great idea. Alternatively you could fill a thermos full of hot tea each morning as well.
Bite the bullet and buy one, if you live in Colorado, you'll have plenty of opportunity to wear it again (and again...)
Have a fun trip!
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse