I always used an easy up gazebo - guaranteed it always rained as soon as you got to the campsite!
Gazebo only takes a few seconds to put up in the rain so you're under shelter fairly quickly.
Put the gazebo over the driver's side door & tailgate.
Large tarp on the ground to keep out the mud, put side walls on the gazebo & get the campfire going - I liked my half oil drum (lengthways) on small wooden folding stand, provides light, heat & BBQ.
Seating was some large plastic storage crates courtesy of Klockner Moeller, I made a few ply lids with thick seating foam.
Car was garaged plus it provided temporary stability/tie down for the gazebo.
If you need more space, simply drive the car out & leave it there.