I just drove the entire length of the Baja Peninsula last year and it's easily the best road trip I've ever done. I saw several RV'ers down there, but the honest truth is that taking any kind of RV or camper south of the border is a bad idea. You really want to do everything you can to try to blend in as much as possible, and an RV or camper does the exact opposite and just draws way too much unwanted attention. You're basically asking to get harassed if you take one of those.
Yep, I've actually seen this quite a bit in traveler/ex-pat vlogs on YouTube. Common denominator was most of them being in some sort of RV/motorhome and pretty much every one of them had to pay bribes.