You may want to check with Sportsmobile to see if they can connect you with latest 4X4 converters for their Ford E-Series van campers. If I recall correctly, years ago they used Quigley for their 4X4, but don’t know what company they use now, or if done in-house.
I would think a 31-foot Class C would be a bit large to go off-road, but if easy terrain it may be OK.
If you want to dream a little, they had some cool 4X4 rigs on display at recent Caravan Salon in Düsseldorf.
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