Every RV Park that We have visited in Mexico has Tent Camping areas and sites. They also all have acceptable to excellent Toilet facilities and Clean up Sinks.
On long weekends thousands of Mexican City Dwellers flock to the Beaches to Camp. Very few have RV 's ,most are in Tents !
You will have no problem finding a place to pitch Your Camp!
Just a note: Mexican Campgrounds typically charge a flat rate for RV's with two persons! Tent Campers are charged by the Person. For this reason RV ers are often asked to vacate the beachfront sites at Xmas because They can squeeze twenty or more people into those sites, which means a whole lot more Profit for the Park,!
It also creates much more wear and tear on the Toilet Facilities Etc.
Rob & Jean
98 Dutch Star Diesel Pusher ..07 Honda CRV AWD