It should fit no problem ... But there is a 6 in. drop from the bottom of the hatch door.
If you can find a piece of 1/2 plywood maybe a 2x4' piece and put something under it to lift it up to level with opening ... it might be easy to slide in and out.
I'm thinking you got an easy 23 high by 33 wide opening to work with and easy 43 deep with hatch closed and seats down ... or easy 32 deep with hatch up and seats back
let us know
how it goes.
wait this is starting to sound like a keg ... ... ... think the 1/2 in plywood will still apply seats up ... slide it in and a couple of nice blocks of foam to keep it in place.