Some thoughts on the oven.
Some of what bad about the oven is their design, some is the size.
The thing that makes a good oven is the ability to maintain temp and there is little in a RV oven that does this. The metal is thin and cool quickly. Since it is also small, opening the door causes the air to cool quickly too.
When I watch my oven I notice that to heat it up the flame is large. This heats the bottom up to high and turns your cookie sheet in to a fry pan. Once the oven is up to temp the flame drops to a much smaller maintaining size. Opening the door reduces the temp and the flame comes back up.
The pizza stone does more than protects the food from the burner, it also absorbs heat and slowly releases it keeping the oven at a more even heat.
A cookie sheet on the rack below the food helps because it blocks the direct heat from reaching the bottom of the food,
We use our oven each trip and I've taken to over heating it and then turning it down when I put the food in. It will drop in temp rather quickly but wont need the BIG flame to get it back up to temp and wont as long as the door isn't open much or for long. It has helped even without a stone or airbake pans.