Ntsqd, Good write up all the necessary stuff is in your post for anybody need to travel in Baja. Let me add to his discussion.
The YAESU FT2900R is a great choice I love mine. Yes, it is true it is now discontinued and replaced with the FT2980R. And it gets the same great reviews. What I do is always buy the programming software/cable from "rtsystems" to allow DIY programming the radio for the frequencies you want. And yes, always either buy with the MARs mod or do it yourself from help from various HAM forums. The MARs mod allows transmit and receive across several bands including the band for Family radio which is allowed in the US without getting in trouble with the feds. For a list of commonly used race frequencies for both Baja and the states search "race-dezert" or contact one of the radio sellers like "PCI Race radios" or "Rugged radios”.
Other random PaulW comments:
Forget marine radios. Low power and not programmable. However we note that they are in wide use in the Baja Campos to allow communication between homes that are close together.
Forget no ground plane antennas they are too tall.
Yes, bite the bullet and use an NMO mount. Magnetic mounts are for temporary use, like a new guy being added to the chase crew. We see a lot of Mag mounts these days for casual desert driving, but never on a race rig because they tend to fall off due to bushes and bumps.
All the aviation vendors sell the good multistrand coax.
Buy or borrow an SWR device to tune your antenna. They come with instructions. Having one in hand allows quick replacement for that damaged or lost whip. Of course, all the RACE radio vendors (Rugged or PCI) will sell you the whip already cut to your choice of frequencies. Typical radio vendor antenna does not come tuned. Buy from a radio seller and carry an extra whip in Baja because they are just not available. Pre-tuned is good.
CB radios don’t work in Baja due to low power, short distance range, and nobody to talk to. For dual use in the states and in Baja I have both types in my latest rig.
PaulW