I can speak with some authority since I'm on my second Sport Trac after having two Rangers.
The price you got sounds good and the miles are low for the year.
In my case it was simply the fact that my kids got too big to fit in the Ranger ext cab.
* Sport Trac seats are vastly more comfortable than Ranger seats.
* If it has 4 wheel disc brakes, they are vastly better than Ranger brakes.
* Buy new shocks immediately if they haven't been replaced already. Stockers are way too soft. Monroe Sensa Trac or Reflex shocks are fine. The '07-up has a different suspension and the shocks are not a problem.
* Change all the fluids, especially the transmission and t-case if you can't be sure it's been done. The manual calls for a tranny flush every 30k in even normal use.
* If it came with a bed extender, the short bed is livable.
*
www.zabteck.com has some parts like ignition and CAI and is inexpensive.
* CAI, Gibson exhaust, and a tuner like an XCal2 will help the mpg. Headers will not.
* If it came with 255/70-16 tires it will have 4.10 gears. If it came with 235/70-16 or 235/75-15 tires it will have 3.73 gears.
I love mine.
More info is at
www.mysporttrac.com. Also
www.explorerforum.com has a Sport Trac section. I am JohnnyO at both of those sites also.