https://www.amazon.com/dp/B004O74Z0G?ref=ppx_pop_mob_ap_share
We bought this for our Y, yet to use it. The separate screen area is ideal, imo. No dirty shoes in the tent!
RTT's are awesome. i was mainly curious about this type of tent.
There are a lot of different versions of these, but you could add on to your van with an SUV tent.
You could try a car seat mattress but they don't seem to be good for tall people.
Other than that, the three of you can spoon with the back seats down... Haha just kidding, but I'm out of ideas!