Finally, a thread I can sink my teeth into!!! I ride a KLR 250 and think nothing of loading up and heading out for a weekend of riding and caving, with all camping and caving gear loaded onto my workhorse, and my destination 300 miles away.
I've got an '04 KLR 250, with the front sprocket geared one tooth higher, and the carb jetted one jet size higher than stock. I cut the rack off a '75 Yamaha RD 350, and with some mods, it ended up replacing the stock toolbag as a great luggage rack. The saddlebags from Kawasaki for the KLR650 fit my bike perfectly, now that they have the rack to strap to. I use a Cabela's dry bag, which is around 12"x12"x27" and is top loading. I already own a bunch of micro-light camping gear, including an iso-butane stove small enough that it fits, with fuel, into my tin camping cup. My only real problem with long distance was the front fender tended to wobble at speeds over 50, so I made an aluminum fender stabilizer and that solved that problem.
It's fun as hell to be able to ride several hundred miles through the twisty West Virginia back roads, then unload enough camping gear to live well for a week, and still have all my caving gear, plus a motorcycle to go exploring the trails with!!
Here is a picture with my buddys 650 on a trip last summer. I'll have to take some pics of the rack and fender stabilizer if anyone is interested.