Truck mounted tents are horrible. Once it's set up, your vehicle is immobilized until it's put away. There's been plenty of situations where I needed to drive my vehicle I couldn't imagine spending 30-60 mins putting my tent away every time I wanted to goto the store to get more beer, then spending another 30-60 mins putting it back.
Plus they are HIGHLY dependant on your vehicle being level, and since when does that ever happen. At least with a tent you can put it in a level place or make your own level camp spot.
Just go on Amazon and get a nice tent
I got this one 3 years ago and it's holding up great. Even through some crazy storms where I thought it'd be a lot more flimsy.
https://www.amazon.com/gp/product/B00VFGKUIK
It sets up really fast. Like, I can set it up myself in under 30 seconds, fast.
It fits a queen size mattress and doesn't even take up half the space.
I'm not 6 foot tall though, and it says the ceiling is 6' tall, so you might be rubbing the top of you head on the ceiling.
I love mine though, and would recommend it to anyone looking for a large tent for car camping.
https://www.amazon.com/gp/product/B00VFGKUIK
For car camping, this instant cabin is awesome. Room to stand up, a queen size air mattress, you'll be living in luxury with this thing.
https://www.amazon.com/gp/product/B00VFGKUIK
I've got this cabin tent and love it. It sets up so fast, my fastest time setting it up is 23 seconds.
My favorite thing about backpacking is being alone, but camping with friends at a campground is fun too espeically when cute women tag along.
My tent is a Copper Spur UL2, which is more than enough for me but hey bigger is better right especially when you can afford the weight right?