That goes without saying. Will probably take at least 10 years to achieve.
1st step would be for Texas to sue for return of Fed confiscated land.
Ain't happening. The deal was that Texas gave up all the extra lands for the federal government purchase of Texan debt at the time of annexation. As a Texan I am not sure I'd even want part of New Mexico and Colorado to be incoroporated into our state. It would bring in too many blue people.