2 Cents Worth
Folding Oklahoma into Texas ain't gonna happen, noway, nohow.
Ditto for blending Arizona and New Mexico (after the POD).
Best bet would be to make Alaska a National Reserve Territory (then they discover oil...) and turn Hawaii into a puppet state under the old royal family (if any are left). Then release Puerto Rico and recognize its independence (as another puppet state.)
OR (evil grin here)
Post 1900, the US incorporates all its Pacific holdings as the State of Isola, including the Philippines, retains Cuba, and incorporates all Caribbean holdings, including Puerto Rico as the State of Columbus. Alaska remains a Federal Trust, as does Oklahoma (for the Amerindians). Have some Constitutional whiz kid get a successful petition/referendum going to reincorporate West Virginia back into its Mama State (the Civil War split being un-Constitutional as all get out.)
Next, sometime in the 1950s, the Kanamits land and solve all mankind's problems.