Going to talk to a guy that has a 2000 KLX300 for sale today, he has a 36mm mikuni pumper carb on it and good bark busters plus other goodies. Pretty good price I think at 1500. The KTM would be very nice but they aint cheap around here and no dealers for miles. Mahart the DRZ is an option too, Ive heared nothing but good things about them.
Pumper carb is a great mod for the kawasakis that came with a CV carb,my Super Sherpa I recently bought was a slug that had to be spanked to get out of it's own way,plus had to be ethered to start when cold,swapped on a TM33 mikuni and now it fires instantly,and has right now power(not a lot more,but don't have to hammer it just to move along).Was a great fit as dimensions matched the original carb,just had to cut and weld the throttle cable bracket to clear the tank. Brand new carb on ebay < $250,jetting seems good,rich on top but I'll open up the airbox before rejetting.
But if you have access to tougher terrain than just trails,you might consider a trials bike,bought one a couple of years ago and now my skill has improved tremendously,didn't think that would be possible once past 50,but I can tell a helluva lot of difference in my bike handling,even when riding my Bonneville,I can turn and maneuver so much better.