Yamaha TW200. It's like an off-road cruiser bike, or a MiniTrail 70 after adolescence. It won't keep up with the 400s and 650s on the highway, but you'll pass them when they fall down off the pavement. Many TWs have kept up with larger bikes on the Trans-American Trail, but they have to be run wide open. Not a problem, because the bike really has no bad habits and probably has the most rock-solid dependability in motorcycledom. It also has a H4 Halogen composite headlight that does a good job at night.
The stock gearing is somewhere between alligator and goat, kind of mule-like, actually. Picking up a tooth on the countershaft and dropping a couple teeth on the rear wheel will see a pretty dependable 65mph highway speed, but be forewarned that a stiff headwind will knock you down to 55 and a downshift pretty quick. Drafting tucked up against the white line to see road hazards 50-60 feet behind a transport truck will let you make 65mph on the interstate in a headwind. First gear will still be low enough for dual-sport roads. If you are going to be on dualsport roads instead of off-road, might as well go ahead and change the sprockets and chain because the stock chain is junk and will only last a couple thousand miles, taking the sprockets with it. I'll be able to give you a better idea of a re-geared TW's capabilities after the Texas Adventure Ride in Junction the last weekend of this month.
The TW's over-sized tires will take some getting used to, but once acclimated, every time you look at a new dualsport your first thought will be "Needs bigger tires." Once you learn to trust the bike you can drag footpegs in the twisties.
There isn't much aftermarket support for the TW200, but many of it's parts are used on other models. Cycleracks makes super strong front and rear racks. That is the only aftermarket specifically for the TW for off-road and dualsport. There is a new company importing TW accessories from the booming TW aftermarket in Japan, but it's mostly street-oriented stuff and is very expensive. Come on, guys, $400+ for a single-cylinder exhaust is rediculous.
Dealers do not carry TW-specific parts, though parts are realatively easy to find online. American Motorcycle Tire carries the OEM Bridgestones, the JDM Bridgestones, and the Cheng Shin knock-offs of the OEM Bridgestones, along with the appropriate tubes. Rear Bridgestones run $95 delivered, and the fronts run about $65. The Cheng Shins are about $20 cheaper. I replaced the front tire at 6000 miles, still running the original rear, and it has several thousand miles to go at 8575 miles.
Here's a list of all the parts I've needed to replace on the bike in 8575 miles:
2 spark plugs.
3 oil filters.
Chain and sprockets.
Front tire and tube.
Main jet.
That's it. I would still be on the stock sprockets had I replaced the chain when I bought the bike.