Drive to Mariposa for Yosemite trip. Rented a house in Mariposa by AirBnB since that is the only one we could find at a short notice.  Although we had sen on TV and the signs on the freeway approaching the area that reservations were required, we still went without a reservation. 

Found out there is no way to get in without a reservation and the reservations are done online only on the first of the month for the next moth. 

The only way to get in was with the local public bus.  If we took the bus, no need for reservations to get in.  The National Parks service at Yosemite limited the number of cars that could get into the park to 3,500 a day.