Given those requirements...I'd go with my first bike....a Honda XR650L. Add these items:
Clarke 4.0 gallon tank.
Happy trails aluminum panniers and rack
Garmin 276/376C GPS on a MGV Touratech Rally Mount
Out of the box, the 30 hp XRL is a great all-around dual sport. I don't like to fiddle with stock jetting or exhaust too much, and found that with the idle mixture adjustment mine would work great from sea level to 11,000 feet. For long highway trips I'd put a cooler spark plug in. Granted, you're gonna want to play with the seat foam a bit...as the very definition of "monkey butt" will become very apparent after about 50-70 miles in the saddle. But this allows for frequent rest stops and meeting the locals...
Great off road, decent on road (I put 4000 miles on mine in 3 months...). Reliablility is top notch, and you can damn near find parts along the road in Baja....You don't have to worry about coolant or doohickeys.
The downside....
Small charging system....you can't really add heated grips, PIAAs, heated vest, etc.....( with the KLR it'll have more juice).
Lightweight for the road....you'll get blown around by semi's and wind....try to stay to the secondary roads.
Two up...fine going around the block to the local coffee shop...bad going out of town. (Two up I'd go with the BMW F650).
HTH..
-H-