California to Central America

I'm considering driving as far south as my civic will take me. (If this falls through I'm heading to Alaska instead. No, really) I've got all my camping gear ready, what else do I need? I've done some searching and it looks like I don't need to bother getting visas or anything other than my pink slip and my passport really, can anyone confirm this? Also, what vaccinations would you all suggest? I've heard the malaria one is basically a waste as there are too many strains to vaccinate against??

I speak some Spanish, and have a translator on my phone. I know it will be $1K or less for gas, and a few hundred for border crossing fees/taxes/insurance. I'm hoping between camping and couchsurfing.org I won't have to get many hotel or even hostels. I plan on livng pretty cheap; hoping I can get away with $3-4K for the whole trip. I would also be interested in possibly staying somewhere down there if I could get a job, but have no idea how that'd work, or how much I could make. Ive got a BA in history and have been told I can teach English down there, anyone have experience with that?

Anything (quite a few I'm sure) I'm not planning for and should be??

And anyone know of a map program that works south of mexico? I couldn't get this one or google to navigate anything south of there, even though it shows all the roads/cities fine.

And anyone need a ride south? =]