A CPAP is not too much of a hindrance, most only draw a max of 70 watts with the humidifier, considerably less without one. and a 2 battery set even of group 27 rv/marine batteries will handle overnight. you can either run off 12 volts directly using a 12 volt power cord, or on 120 volt from campground supply or an inverter if shore power isn't available.
If you are running from the batteries you will need to recharge the next day either by running a generator, running the drive engine, or by solar.
On the sprinter recommendations, I would agree if that is within your budget. If not, then a small class B+ or C on either a Ford or Chevy chassis may be more realistic, plenty of them around especially if you are looking at 10 years old.