Sorry, I didn't see this as it was posted in Open Discussion and not in ePlaya Feedback. I gave it a nudge to the right board, as that's a better fit for a discussion about operation of the site.
Joe's closest to hitting the nail on the head. The site's mysql search functionality works really well, but doesn't index various common words. Elderberry's right in that if you want to go the dumb search route (that is, not search by keywords and just type random words that come into your head), using something like google or bing with those words plus 'eplaya' will get you the best results (all the major search engines index our site). Eric is right in that if you're smart and search by keywords, you get better results (the same is true on just about every search engine).
You can also get better results when searching on ePlaya sometimes by clicking on the advanced search button and narrowing the focus. You can specify that you're looking for words in topic titles or in topics and messages, or for stuff posted by a specific person (great for trying to find an old conversation, if you've been on the site for a while), or you can choose just a specific board or boards to look in.
All searching aside, you can expect to see posts about RV shares for the 2016 event on the aptly titled "
Rideshares and Resource Sharing" board. There's very little in there now, because it's still really early in the season. Good luck in finding a connection.