Also, if you are considering the hybrid version the rear seats do not fold flat.

 

I am 6'3" and I spent many nights last summer and a few in this winter sleeping in the back, fully stretched out with the front seat pushed up about halfway; if I push it all the way there's a lot of extra room but it also creates more space in the rear footwell to fill. I have a single subwoofer I run in the cargo area that I move into the footwell when making bed and it comes very close to smoothly extending the sleeping surface. I also used to turn the rear seat's headrest around 180° and put it back in as that helps extend the plane as well, been experimenting lately with other methods and you'll also find what works best for you. The slight incline of the rear seat is actually kind of comfortable once I get settled and after a few minutes I barely notice it through my ~2" thick sleeping pad + whatever sleeping bag I'm using. I usually set up on the passenger side as it has more space when you put the rear seat down but if it was completely necessary you could be on the narrower 40% side and be okay.

You'd want rain guards so you can leave the windows cracked, and my most recent overnighter a few weeks ago showed me that even with the windows down about 1" each you can still end up with condensation everywhere if there's no night breeze. I'm currently working on using a PC case fan (built to be very quiet, also runs on 12v) on low RPM to keep air moving through the night and hopefully solve that. When I hooked it up to a bench power supply with some in-line resistors to bring the speed/noise down, I could barely hear it running and it still moved enough air that I wouldn't be worried about waking up underwater.

This is how we slept at the Mt. St. Helens trailhead last summer, we were almost certainly the warmest/most comfortable of our group that night:

 

Almost 7' in my XLE Premium hybrid. As others have said, the rear seat is not quite flat, and there is a substantial gap between the top of the rear seat and the back of the front seat. Perhaps raising the headrest on the rear seat would help fill that gap.

 

Cool! Thank you, folks! It's very appreciated.

Just needed to know if I should keep looking into getting one, as being able to sleep in it is a top priority given the path I follow. I've spent around 300 nights in my '97 RAV4. I wish the new ones had the ground clearance of a first generation model with a set of big wheels, but I wouldn't complain about the improved gas mileage they get nowadays.

Looks like a cozy nest, Mr_Flux! Thanks for the tall-person beta.

 

When the time comes for new tires the 5th gens will swap from 225/65r17 to 245/65r17 with no issue, which gives a bit of clearance, and there are also many spacer/spring lifts available. I've seen a few people that run both and so far that doesn't seem to cause an issue but I can't confirm for sure.

 

I just remembered that I had bookmarked this for a rainy day. You may consider something similar but modified for your needs-

Spirit of Adventure: Rav4 Folding Bed Platform

Wanted a folding bed platform to make the Spirit of Adventure more versatile without having to add a rooftop tent. Whole thing folds up into the trunk space, with room for a backpack or two atop the platform. Minimal underneath storage; two jackets, spare nalgen, and a small blanket stuffed...

www.rav4world.com

 

Today I came here for help as I was in IKEA. And, this is kinda general idea for everyone, not specific on this tread.

Plus, this is about straight dimensions and fitting straight items.

Today, I managed to fit IKEA 6 wardrobe boards which are 1.91*0.60m but had to push front seats all the way. All flat boards were behind the front seats and not through the middle arm rest.

For everyone who are trying to fit few slippers or any straight items, do not try to go above 1.7m if your size is above Large or 1.8m for any. 1.6m is the best size that you can drive comfortable.

Cheers...