You have to be very aware of who knows what. When we asked about vehicles at the Mexican Consulate they were very up front about the fact that they knew nothing about it and that the information was not available to them because it was not something that they covered. They were basically immigration. This was further illustrated when we started planing our menaje de casa. Yes, you get the final paperwork done through them, but it turns out that there is a defined period of time after getting your residency and when you can use it. They weren't really aware of that until we were ready to do ours. We missed the window, but it worked out well anyway.
Vehicles? I'm with gtla9111. Don't think you can nationalize anything of the age of your Honda, and when the time comes for your trailer/RV, you will have the same limitations. When you figure in the cost of the customs broker, the taxes and fees, you are still better off buying something here. You can buy a brand new March for under 200,000p.
IMSS-check it out. For our age, it is about $465 US a year, each. Many preexisting conditions are excluded. It's better than nothing, and in some areas I hear it's great. Here, for example, Karl has it. He needs to have his gall bladder removed. Free with his IMSS, big incision, etc. At the private hospital, arthroscopically, it's $450 US all included, minimal recovery time. He opted to go the private route. Lots of homework to be done.