The main reason is because the areas of NM where I am looking are MUCH MUCH closer to being central to all the areas I love to visit. The gas and maintenance savings alone of dragging a FIFTH back and forth across the country will likely pay for the land, and then add the fact of the maintenance and wear and tear of round trips from SE Texas back to California / Utah / Colorado / AZ / New Mexico. Those are the places I love to visit the most, so makes sense to keep the 5th in New Mexico (or SE AZ is another possibility).
Basically, it will allow me to keep the 5th and not have to resell it at the end of the trip, and I can enjoy it for years as a vacation resort when not traveling.
I will have to invest in some land, but as long as I do it wisely, real estate should hold at least 80% of its value, and it might even go up over time. Much wiser spending the money there then on GAS and maintenance and depreciation which has a guaranteed zero / negative return.
I am not really so interested in seeing the entire country so to speak (already done that), but I am more focused on the places I love to visit. Oh yah, Idaho and Montana are also cool, but NM is also a LOT closer to those places as well.