Not familiar with the popup, and he said it was coming from the roof near the AC.
The smoke detector should be on the ceiling somewhere. (9VDC issue?)
The Propane detector should be near the floor.
Is the smoke hard wired into the DC system of the popup like on the 5'ers?
If so, the 12 lead acid battery could be low or not charging.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW