Well, it's entirely up to you as far as addressing the Doohickey (engine part). Mine was fine at 4K, but I've seen some broken, and $40 for the parts to address it is pretty cheap for Peace of Mind.
Check out http://www.klr650.marknet.us/doohickey.html
for the procedure, and consider it. During Doohickey Days, very skilled guys can address it with you and it doesn't take long. There's a good bunch of guys in your area, also..
As far as what you're after for riding, you picked a great bike!! I've wandered around your area and up in da U.P., eh, and it's a blast to ride the bike on single and double track trails!!
Here's a pic of a buddy of mine while we were wandering around the Keewana Penn, north of Houghton, MI.
And me, above Copper Harbor..
And my bike and Double A (also a member here) at a park on Lake Superior in the same area.
I rode the entire weekend on 1/2 worn Anakee tires, that are 90% street tires.. Here's where I wandered in Iowa last fall on my current 50/50 tires..
And here's my camp during Doohickey Days at Mogwai's place, right up in your neck of the woods..
And later that weekend...
The KLR will go pretty much wherever you want it to..