Newbienac wrote:
.... Were I to stay pretty much in the high desert areas would it literally be the top third of say, Texas and New Mexico for instance?
Yes, the NW corner of Tx, most of southern NM and the eastern 1/4 of Az are high desert, above 4,000 ft.
Its a bit of a balancing act, and each year is slightly different: if you get there too early you'll run in to below freezing temps at night, if you get there too late you'll run into 90 degree heat during the day in lower elevations.
PS: my comments were only directed to the southern portion of your route (I10) from Fla to Ca. If you chose to head further north at that time of year, its a whole different animal, including spring snowstorms in some areas.