Warm beer...
As an ice chest guy I will add my experience here. Keep in mind I am a big guy that loves to eat! Having just spent 3 months in Central America, I found that ice is found just about anywhere. Most tiendas and gas stations have it any more. It was nice never having to look for propane..(check out the yahoo group '99 Days to Panama' for some of the difficulties with that). True that in Mexico there are nearly as many propane automobile fueling stations as there are gas stations, the problem is that their fittings are quite different I am told and they can't fill bottles or frame mount tanks.
As far as power for running things on 12v, of course the more stuff you need power for, the more certain you will be to need a solar panel(s). Once we left Mexico, we never had a 110v plug in again. So don't count on that.
We don't drink beer but do like our "agua mineral" or club soda and fresh limes and we like it cold. Ice does the job just fine. Our next purchase will be a better ice chest (a 6 day model and a bit larger)
Looking at the price of Engel reefers makes it a no-brainer for me. That is another month or more in CA!
I need to add that since my wife has MS and was using an injectable med that needed to be kept cold got us looking around for a way to do that other than ice. The solution was that she stopped taking the med. Much better, no side effects and no problem for storage....no worsening of the disease, thank goodness.
Our friends, Carla and Heiko who are traveling for a year in CA and SA as well as our friends Yasha and Juergen who are doing the same, both have hard sided truck campers with solar arrays that could run a small town. They both have fullsize fridges and enjoy frozen food and cold beer whenever. Note they are completely self contained and have Six-Pac and Bigfoot campers respectively. They never need a plugin and can stay somewhere as long as the propane tanks last....Heiko has another tank stuffed in a closet just to make sure he doesn't run out. Yasha and Juergen are actually on an openended trip 18 months long already. See:
http://dare2go.com for Yasha and Juergens site.
I am of the thought 'less is more' unless you are actually fulltiming in the rig, and having worked as a mechanic and in maintenance all my life, I am completely convinced that I want as few systems that can break as possible. We were camped next to a guy in Mexico who had some system problems with reefer, air conditioner and electrical....he found someone to do the electric but the other two required trips back to the states.
Brian