I don't know the furnace brand, but I'm sure the blower is fairly easy to replace once you get to it and verify it's the source of the noise. Possibly, it could be lubricated, but that's just a wild guess. Once you get to the part, you'll be able to tell more.
I've never gotten into the furnace in my trailer, but I think you do so from the exhaust panel on the outside.
Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew