The best thing to do is to talk with the RV park manager and explain what you would like to do. They will either allow or not.
One way to get customers is to put on a demonstration. Ask the park managment if you can put on a demo in one of the club room or central area of the park. Post flyers with date and time. I've been to numerous of these type of demos and the folks always sold quite a few producs after the demos.
Another way to create interest is to do your spinning in your campsite where you can be seen by folks walking by. Some will stop out of curiosity and buy becuse they like what the see. We have sold many products this way when we were selling on the road.