Travel from McAllen Tx to Kalispell MT in March?

Aim for I90 in eastern Montana or Wyoming. Cross the divide on that, and take US93 north. I90 has a couple of passes, but they are all freeway quality.

Or aim for US2, and cross the divide on that. US2 has just one pass, and that is relatively low. But getting to it will involve more wind swept plains driving.

Another option is diagonally across NM and Utah (Cortez, Moab and Price) to I15 in Provo. But that still passes through the high junction of I15 and I90.