Residential M/W are typically installed inside a non vented cabinet in a house. (not to be confused with a microwave that also acts as a range vent either venting back into the room or overhead through a duct and out of the roof typically) Did you old unit also have a power vent for the range?
RV units are 110v and plug in just like at home. Often they are mounted differently. You should be able to use any M/W that fits the space and offers a similar range vent (if any) as long as you can plug it in and secure it properly.