You are pretty much on your own when it comes to RVs. But I'd start by searching this forum for ideas. What works for car, pickups, vans, etc. will work for RVs too especially when it comes to noise abatement.
One advantage some RVs have is an on-board generator which allows using a base-station type amplifier. This requires special attention to antenna construction, grounding, and mounting. http://off-roadhams.com/
You can try here, but I didn't see much on actual installation.