In the case of your specific coach, a marine wax specifically designed for gelcoat fiberglass. It will probably provide the longest lasting protection short of clearcoat paint. Many use a floor polish called Zep Wet Look (aka Red Max Pro) which has a big following around here and on other RV sites. It is basically similiar to a thin plastic clear coating which can be long lasting, and can out last wax. You can find similiar plastic coating in the marine/RV markets that are long lasting, but more expensive because they serve the marine and RV markets.