From the NPS Yosemite Camping FAQ
http://www.nps.gov/yose/planyourvisit/campingfaq.htmI made a reservation for an RV nonelectric campsite but only have a tent. Can I still use the campsite?Some campsites are listed on recreation.gov as "RV nonelectric." This means the campsite is best suited for RVs and trailers. While you aren't required to use an RV in one of these campsites, they are listed as RV only because they generally do not have adequate or level space to pitch a tent. If you arrive and find that the campsite doesn't work for you and/or your tent, we will not be able to move you to a different campsite. You should always read the site alerts and book a site that is appropriate for the equipment you will be camping in. If you have questions about a specific campsite, you can call the campground office at the phone number listed in your reservation.