I can't point to a specific reference but my feeling is it possibly depends on the type of tenant.

If It is the trailer park down the road, with Mobile homes, off their wheels on blocks, with long term tenants that either rent the MH or own it, It feels like an E.

RV Park with primarily Short Term users (couple of nights to a couple of weeks) with a few several month type construction workers - probably that feels more a C. Of course those usually have some of the amenities mentioned earlier.