Hi cajunfj40. I came across your thread today and have some suggestions you may want to try out.
1. Find a used Scanguage. I picked mine up for $60 off Craigslist several years back. Best money I have spent on my hypermiling endeavors! It truly turns driving into a fun mpg game. The UltraGauge and MPGuino are both woth considering, along with Torque and others. I'm partial to the SG myself.
2. Read up on Wayne Gerdes. Reread, then reread and implement. He coined the term "hypermiler", and for good reason. I've read that he got anywhere from 40-70 mpg out of his Ford Ranger. Using his techniques to some degree should push you over 20, and perhaps even higher.
3. Aero mods. These are going to be worthwhile on your Explorer, whose coefficient of drag is probably around 0.40. Aerohead goes by "2% aero reduction = 1% fuel savings." This doesn't sound too good. However, the more un-aero the vehicle, the greater the benefit of the mod, usually. A belly pan and grill block would help aero and warm up times
I have more, but work beckons early in the a.m.
Edit: According to
Ecomodder's handy dandy drag chart, your Cd is 0.43