A 40 degree drop in three hours is way more than expected, sounds like you have a good one. But don'tr expect it to cool warm beer (or soda) that fast
Some units have a small freezer, just about big enough for two mini ice trays or 4 Eskimo Pies.
If original, your refrigerator
is probably the early style (square edge boiler cover) and is more sensitive to being level when operating. They used to come with a small "Bull's-eye" level (that are still easy to find at WalMart or any RV store). Usual rule of thumb is to be within 1/2 bubble width of level. Consequences of running out of level is a clogged cooling system that will shut down the refrigerator
But, if it has a round (curved) boiler cover, it's not as sensitive and the trailer need only be level enough to be "comfortable". (Their words, not mine)
Let us know how the Gas works, that's what you will use most of the time while camping.