We also are full-timers (in a '86 Avion 34V) and, like your wife, cook most of our meals (both of us together, usually). We have the 22" MagicChef 4 burner/gas oven, and last August installed the Dometic Microwave/convection oven.
The learning curve on the convection is steep! First thing you have to realize is that the forced air movement of the convection causes things to dry out/be crispier than a conventional oven. Additionally, we have learned thru many hours of research and experimentation is that in converting recipes to the convection oven a good STARTING point is to do ONE of the following: Reduce the temperature by 25 degrees OR decrease the cooking time by 25%. From that point you will probably have to do some fine tuning to get the desired results.
We have also learned that breads and cakes are doable in the convection but are much more trickier. Your first few attempts will likely end in disaster!
Boondocking, obviously, would not be possible with our set up without the gas unit. There are no combo units like you asked about (that we know of) available for RV use (there are some available for LARGE commercial kitchen use, but they are huge!).
After 5 months of use, we can say we like the convection (when we are NOT paying for electric) but this unit can draw a lot of amps (such that in an RV with 30 amp service it may be quite frustrating when full timing with it: we have converted our unit to 50amp service so it is not an issue). We use the gas for some things and the convection for others. If we had to give one up, it would be the convection.
Linear Mode
