I have slept in my E a number of times and I find getting out from the back very difficult. An inside latch for the rear window and taligate would make the E and excellent overnighter.

Ps. passenger side arm rest has been wished for many times by my wife.

Do a search. I believe someone posted a mod on the tail gate that permitted opening from the inside. It involved cutting through the cover and accessing the release mechanism. It made him happy.