The 2-door jeep Wrangler is only just perfect for two adults & full gear. The backseat folds back unto itself, but it doesn't give that much more space.
There's a slant - it's not flush.
I wanted to remove the backseat and leave it inside our condo for the week...it didn't come out! WTH Ford is your problem? Minivans you can remove the rear seat, unless it's the hide-away version.
I have twice the trunk space in my Prius - I've ferried four adult divers, cold water gear, eight tanks, and two coolers.
Only problem? Ground clearance. That loaded, my car was scratching speed bumps in the shopping mall (those big fat ones).
Though I still got over 40mpg on the highway.
I was appalled at the Jeep's mpg while in Maui. Two and a half tanks - 75$ per full fill-up, just to do 700 miles. Fun to drive though! To "Road to Hana" was a blast with the jeep. Not for ground clearance, but the view! You sit high, see far, little obstructions to your view.
In this car-ruled world - you can't have fun, room & mpg all at the same time. Even a Lexus CT200h - basically a sexed up Prius in a Matrix-delux-interior - isn't that different.
I would have rented instead a Ford Escape Hybrid - that's one high clearance I like with twice the mpg as a wrangler...none available though.
The Prius rentals were all rented out too. If you don't want to pay 100$ per day (and gas might be another 20 per day) - you'll just have to park on the road and walk to the non-paved roads to the many hidden - hard to reach beaches.