We, too are sold on exiting through Lukeville/Sonoyta. If you don't want to dry camp at the beautiful Organ Pipe National Park, there are a couple of nice parks in Ajo that give great Good Sam and Passport America discounts. We like Shadow Ridge.
We quit entering there two years ago when they went through a several year program that, "It's not the law, it's for the good of Mexico" made entering tedious. Pet papers, going through freezers and refrigerators and asking that you voluntarily surrender your meat, etc. I haven't heard of anyone having that happen for two years now.
Please don't get me wrong, the law is the law, but when they are creating their own rules it was tough to know what to do.
This year on our way out he will be driving the moho and I'll be driving a large SUV pulling a 10 foot cargo trailer. Hopefully the sharp turns won't be an issue for me, but I'll have practice towing by the time we get to the border!