I would just say that a 9 year old bike with low mileage is still a 9 year old bike, and there are a lot more things to break on a KLR than there are on a TW.
$1500 was your starting budget from what you said in your posts, so you're way over budget on purchase price alone, and unless you're a remarkably lucky individual that used bike bargain (like all used vehicle bargains) is going to wind up costing you more than you would like on the back end.
I'm a little jaded as I've had particularly bad luck with used cars and trucks, so with vehicles wherein an unexpected mechanical failure might just mean that you die (i.e., motorcycles like the KLR capable of 100mph+ speeds) I prefer to pay upfront for a solid machine than paying later for parts and labor or worse, medical bills and coffins.
It sounds like you're pretty sold on this used bike (aka somebody else's problem) already, but I beg you to be realistic as to what you're signing up for. in the wrong hands, 400 miles are plenty to wreck a bike. 4000 miles plus 9 years means that you should plan on replacing pretty much everything made of rubber or grease, and once you've done that you're pretty close to bridging the gap between your used bike and a brand new one that works better on the day you pick it up.
Who knows, maybe you'll be lucky and your $2200 KLR will be a winner, but most likely some dude is going to be counting $2200 bucks that he doesn't have to spend on parts and labor while you're wishing that you had another $2200 to spend on all of the parts and labor that the bike still needs.
Hope your luck is better than mine has been if you go through with it!