Last summer I rode from Vancouver, BC to SF with a cpap. I used the Transend Auto CPAP.

CPAP.com - Transcend Auto Travel CPAP Machine with EZEX

I also brought the Transend Multi Night Battery

CPAP.com - Transcend Multi-Night Battery

It worked well. I charged the battery at lunch or at the campsight and never ran out of power and used it every night.

On a prior shorter tour I brought my Resmed S9 with humidifier without the battery. Stayed in motels. It's a lot bigger and heavier.

The Transend worked well and was never a big problem.

If you have more detailed questions, just ask.