You need a remote thermocouple unit. Even a brief door opening greatly alters oven temperature. They are not expensive, even a unit designed to be used with a BBQ grill will work.
Those may be purchased for <$50.
After I matched the oven temp knob with oven temperature, and placed 4 tile squares in the bottom of the oven, it baked very evenly and maintained a reasonably even temperature during baking time. My wife got so good at baking in the RV oven I gained 10# during our Alaska trip.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"