I completely sealed off the lower vent and left 1/4 of the top vent open, vents are both on side of trailer. Under the front of the fridge I have a 1 1/2" gap that I put a vent cover over. The fridge can draw in cooler air from the inside and vent the heat out of the top vent. Seams to be working well. I used Gorilla tape to seal the inside of my vents.
2008 GMC Sierra 3500 SLT DRW D/A 4x4 (Big All)
2006 Ford F350 PSD SRW King Ranch 4x4 (Henry) (Sold)
B&W Companion, 90 Aux Fuel Tank, Scan Gauge II, Curt f/m hitch, Swagman XC
2015 Forest River Sierra 360 PDEK
DW Diane, DS Michael, FB Draco and Sabian