It really depends on how serious you are about the bike.
I don't want to pee on any parades, but pushing a bike outta the bush
sucks!
Can you do the work youself?
If it were me I'd rebuild the crank, it is 14 years old!
Full gasket set, who know what you'll find in the tranny.
Clutch, chain, sprockets, forkseals, cables, brake pads, disks.
Rear shock rebuild, seat cover (duct tape glue on riding gear sucks!)
foot pegs, shifter, levers, brake pedal, grips, bars it the existing
ones are bent. Tires, spokes, rims, wheel bearings, rubber carb manifold, reeds. New air filter
Fork springs of the correct rate and valving helps the front end a ton.
But all stock KDX font ends blow.
All of this is a worst case possibility, but I bet that some of it will
need attention.
Go over the whole bike and check the condition of everything from the
tires to the tail light. All those little bits can add up to a
surprising total in a short time.
Add it all up and compare your total costs against a newer used
bike of the same value and make a decision.
Sorry for the long post, I'm currently rebuilding an 81 RD350lc I got for free that is turning into a cash cow. I could have bought a much
better RD for what I currently have invested in this project,
but its too late to stop now