In Rhode Island, the fridge should work well all year long. As mentioned above, sometimes in high heat, it can affect the efficiency.
You did not mention what RV you have--if the fridge is in a slide, that is a little harder to keep working right in high heat, as there are side vents only, no top vent. May need exhaust fans to remove heat.
Some RV fridges keep ice cream very well--others may just keep it soft, but cold. Having ice cubes is usually not a problem, but hard ice cream may.
Ovens work well, but they aren't as good as the home units.
All of the appliances just take a little getting used to--they aren't as big or efficient as the residential units.
'05 36TK3 Mobile Suites
'10 F450 new to me
'09 F450 Lariat 4x4--died