The suggestion from tatest is a very logical solution .
Get a full size van off lease .
If you are going to have 5 people all of the time you will need that .
Although we dry camp with our travel trailer we also Boat Camp ( in tents ) with our adult kids and other boating friends .
For those trips I take two of the EZ-UP Quik-Shade canopies .
They go up first .
We put one 12 x 12 over the NFS/NPS/BLM picnic table .
Do not skimp , get the 12 x 12 . An 8 x 8 is worthless .
We cook on a coleman stove and this provides shade and rain protection .
The other EZ-UP goes up next in the spot where we pitch our Outfitter quality tent . (Eureka Timberline 6 and Alps Mountaineering Taurus 5 ZF-FG )
We put down a ground cloth under the EZ-UP and then put up our tent .
Our experience is that we stand a 20% chance of some kind of downpour and the EZ-UP keeps our tent and gear dry .
OR if it is REALLY hot the shade over the tent is welcome .
The EZ-UP assures us that we will never be wet . Nothing worse than a wet tent and sleeping bags .
An EZ-UP goes up more quickly with 2 folks but with 4 it goes faster yet .
A full size van would carry the necessary gear you require without a trailer .
We use a gmc diesel extracab pickup with a snugtop canopy .