I had some leftover blue dimpled sub-floor from some home-renos.  Installed
some in the main compartment and in-between the front seats.  Works GREAT.
Feels great on bare feet.  Catches liquids and keeps them off your carpet.
Keeps your feet feeling dry even if some water has entered the van.  Easily
cleans up with a garden hose in case of a coffee spills and dries almost
instantly in the sun.  The blue colour is cheery and garners many
complements from on-lookers.  Is slippery so you can slide stuff around
easily.  (Tie down heavy things when driving.)

I used a longer than necessary piece in the main compartment and it's sort
of like a bathtub front and back.  An extra piece by the door slides under
the main piece to fill in the space.  Can take a picture but haven't
figured out how to post it for you.

Link:
http://www.homedepot.com/p/DMX-1-STEP-100-sq-ft-3-67-ft-x-27-ft-6-in-Unique-Air-Gap-Underlayment-Prevents-Mold-and-Mildew-DMX-1-Step/204494289

gabby