A good solution would also be the foam tiles (anti-fatigue tiles) that you can get at Sears or other places. I got a set at Sears for $19. They have edges that interlock together. One set will cover the area from the back of the front seats all the way to the tailgate. I cut a couple flaps to expose the seat anchors. When I was installing them, I noticed that they are actually quite comfortable and soft. I got them to protect the plastic floor and add some grip for when I carry cargo. I thought, as I noticed how soft they were, that they might actually help if one wanted to roll out a sleeping bag and sleep in their E. I then put a mat, like was originally mentioned in the way back behind the rear seats to protect the tiles from getting dirty and being gauged up by everyday cargo. It is actually a runner that is about a foot and a half wide (almost exact width of rear seat to tailgate) by whatever length you want. they cut it from a roll for about $1.98 a foot. I got 6' of it so I would have extra to protect the side walls if carrying a lot of stuff.
Then, I have the HONDA Carpeted mats that I have in the back seat area and the front seat area. If any of the stuff I got, the runner or the tiles does get damaged, no big deal. Inexpensive and easy to replace.
The HONDA Carpeted mats would be expensive but they are nice and very durable. They clean up pretty easilly if dirty also. I took a ham to my girlfriends for Christmas a couple years ago. The grease and glaze spilled on the mat. I washed it in the wash tub with a stiff brush and some Tide. As good as new.