It doesn't have to be perfectly level, if you can walk around without holding on you are probably within refrigerator operating limits.
My Norcold takes 8 hours or so to cool in the refrigerator section empty, especially if it is over 80 degrees outside. Longer if it has food inside. It also tends to cool faster when on LP (propane) compared to electric. Electric usually is fine once down to temperature, but many users experience better (faster) cooling on gas.
Compressor-style refrigerators (residential) tend to cool down much more quickly, many love them in their RV's. Others who dry camp frequently need to sometimes take extra steps to make sure they have a reliable way to keep the refrigerator under power when not plugged in to a campground power post.
2014 Seneca 37TS
Toads: 2014 Ford Explorer Sport or 2013 Ford Focus ST