Hope it's flat where you live. I am actually looking for something with more power. I have heard the Vstrom 650 is supposed to be more doable 2 up. Not to mention more comfortable for 2 up. Of course you could put in the 705 or 750 kits, then maybe you'd have the power. My buddy did the 705 and loves the power, but for the price you could get a used GS. I have had the wife on my 06 with me and I was quite uncomfortable too. But I am 6'1" so need a little stretch room.
IF you do decide to do it, I would beef up suspension and do the subframe upgrade. If you 2 up and have gear, the bolts have been known to fail.
The main question is an overnite two hours away, or long rides, and frequent. If you are doing it once or twice a year and not going to the mountains, KLR should be fine. But, I do sometimes regret not going with a better 2 up bike, and getting the KLR for my fun bike.
You got red on you.