We heat with propane, we cook with electric
There are plenty of shops around
Too me it seems nobody else has done what you want to do
Buy a brand new RV of a specific model, and then retro grade to a propane fridge
Your in New territory where no man has gone before
There has to be a first for everything, and for this idea, it looks like it is you..
You have a choice be adventurous
Or purchase a different RV
We can't give you info we don't have
Anything can be attempted if you spend enough time money and energy, in many cases it can be accomplished
The point is ...is it worth it, and are you willing to live with results, if it doesn't turn out the way you want it to.
You seem to have picked a project idea, that nobody else has attempted, you are the first we know of, that's wants to do this
Many have bought a.specific RV to get a residential fridge, or bought a. RV to have an lp fridge, but it seems nobody has bought residential and changed to l.p.