This is so easy...
If it's a trailer-sailor, you can use it on land (for sleeping, etc....on the way to the water
) - but your rv won't float.
You can get the sailboat and use a tent and backpack on land (recommended).
How close are you to good water? How fast can you be under way in the sailboat? In my case, I can be sailing a bit sooner than I can find a camping spot on land. If I lived far from good sailing, I might think differently.