Last June, I bought a barely-used 2008 WR-250R with 118 miles on the odometer on a whim, basically because it was dangled in front of my nose at a lowish price ($3,500).
I'm very glad that I got it because it got me back into riding off-road regularly, something I hadn't been doing since 1993.
Now, I'm out there every Sunday. :)
If you ain't done it already, lower the gearing by at least dropping a tooth on the front sprocket (stock is 13 teeth in this country).
I'm using 12/47 sprockets, myself, and the bike is muuuuuuuch better for off-road riding while still hauling the mail on the street (84 mph). :)
I also own a 2009 WR-250F, and I got it street registered so I can legally ride it on my state's public land/trails and connect those trails with stretches of road.
Compared to the WR-250F, the WR-250R is a decent trail bike that can do the job.