We have a 2013 road warrior 300c. While removing the two bedroom receptacles to replace them with receptacles with USB ports I noted that the cavity behind the interior wall has little if any insulation. this appears to be a cavity about a foot deep and the full width of the coach and about 3' in length. There is a little fiberglass here and there but a lot of exterior area with no insulation whatsoever. ideally it should be sprayed with foam but that option is not available for the do it yourself person. next option is to add additional fiberglass but getting fiberglass through a receptacle hole is not practical plus it would undoubtedly settle. The only option I know of is blowin. what do you think? I've insulated the garage floor with 3" of foam after pulling down the 2 fuel tanks and I plan to pull down the coroplast and add more to the floor of the main living area.