I have been using CPAP for years. A couple years tent camping before buying my TC. Started, and continue to use a "RV Deep cycle" battery with invertor. Usually lasts my whole trip. If extended trip, I charge it with Honda during the day for a couple hrs. I have always used my home unit, with humidifier.
Since owning the TC, I carry the battery in truck bed, ahead of wheel well in marine style battery box. In cold weather, bring it into TC in corner of the floor. Overall this works well, never concerened about draining house batteries (×2) or power for CPAP!
My life has changed since using the CPAP. The benifits are so good for me, but not really for this forum...but sufice to say, wouldn't be without it, AND not willing to limit my lifestyle because of it. Made it work for me! Hope you have the positive benifits I have, and don't allow it to limit you!