Where you cross the border depends on where you are coming from and where you are going. We have not crossed at Lukeville because it has never been along the route to where we are going from where we are coming from. We have crossed at Nogales (Mariposa), Tecate, south of Deming, NM (Columbus/Palomas), Los Indios south of McAllen, TX, Laredo, TX (Columbia), and had no problem with any of them. Our first trip in our new Bus was to San Carlos using MX15D because some friends were going there so we tagged along. Since then we have ventured all over Mexico and have now been in 28 states. We drive a 40' motorhome towing our Honda CR-V and are probably too big for Mexico but we seem to manage. Some roads can be narrower than we are used to in the US. In recent years (and still today) there has been a lot of road construction all over Mexico as they build new roads and rebuild old roads. Many roads are now wider and smoother than just a few years ago. But there are still narrow places with lots of rough road. A short trip or a trip without a definite destination might be a good first venture. See our blog over the years which should be linked here in our signature. Get the recommended "Church" book and a good GPS and then research posts on this forum and go through many previous posts. We find Mexico to be very different than many people north of here think it is. We now spend most of our winter months roaming around Mexico and everywhere we go we run into old friends from previous years who have now come to spend winters in Mexico. Some are roamers and some stay in one place or only visit a couple places. We still like finding new places as well as visiting old favorites and meeting up with old friends. Some of the best people we know are now in Mexico - both the Mexicans and other RVers we have met in Mexico. There is much to be learned and lots to prepare for and some travel days can be tough but we find it is well worth the effort. Keep asking questions.