You may have seen this before, but it's worth posting in case you haven't. A friend recently gave me this tip - he is a caravanner, but it would work easily as well with a motorhome. Remove all the soft furnishings. With the cost of replacing a set of seat and bed cushions around £1000, a thief would think twice about taking a van without them. Replacing them may also lead to some suspicion. It will also keep them nice and dry in the winter.