The toll booths were all back to collecting as of Tuesday. You will get a 10 year permit for the MH whether it is solo or towing a car. You can only get a 6 month on the car whether it is a toad or solo. Get all your permits at Nogales( actually between Nogales and km21). Why stand in a line twice. You will have to leave a deposit on the car. I dont think you pay a deposit on the RV. I never have! If they give you a hard time just disconnect the car. Should not be necessary. You can get all of those permits on line. I always get them at the inspection area.
Moisheh