Humidifiers

IMHO humidity (air moisture) will disperse throughout the RV with the furnace air blowing it around. but in the bedroom it will be a good source of white noise.
bumpy

I say put it where you think it will do the best job.

But one thing to be carful about, depending on your sinuses. Outside humidity low and inside will be high. Right now Tucson is 28%. If you crank up humidity inside RV high, some people get nose bleeds or headaches from the humidity changes. No big deal for most people. I'm not a Dr or anything even close to one. Only reason I know is because last year of a couple next to us. They are from a high humidity area and she kept getting nose bleeds while in Yuma, where low humidity is the norm. She eventually went to a Dr and now keeps RV in the 40-50 range. Probably lots on-line about what is best ranges.

Research the different types and the advantages/disadvantages of using a humidifier. The Mayo Clinic recommends keeping the inside relative humidity between 30% and 50%. Humidity levels that are too high (or a contaminated humidifier) can cause problems with mold, mildew, dust mites and airborne bacteria. "Cool mist" or ultrasonic humidifiers are the safest, but all humidifiers must be regularly maintained and cleaned.

Rob
(retired Army nurse)

I would put it close to the cold air return, so the humidified air can be sucked up and circulated throughout the trailer.

Mark