sorry in advance culcune, but i'm going to disagree.
If I didn't need californias certification, I would work the best deal I could on a Hawk before I set off to build a waaay south of the border adv bike.
First, the hawk is(or should be) waay cheaper than the tt250, the engine is stronger ( I have both). Put on mjstef's instruments, a mikune w appropriate jet selection, aftermarket exhaust if you want(not really necessary but will save a few pounds, take a 17t sprocket for the first relatively good road part and switch back to the 15, then maybe even the 14 if you are going into the andes, change out the spokes for good stainless, maybe upgrade the tubes keeping the originals for spares,thro on sealed bearings while you r at it, ziptie and put the wiring sheaths on everywhere u can, put a good quality metal or ceramic fuel filter in line and a very very fine screen in the tank inlet(for baad gas) change out your grips to feel comfortable to your gloved hands,run an extra clutch cable, dot4 in the brakes, grease the hell out everything that moves, replace the stock chain, install your bar end/lever/hand protectors, change out the fork oil to something that fits your loaded weight. maybe buy a more adjustable or resprung rear shock.
attach up one of the aftermarket oil coolers and re do the front fender. add a good bash plate, and call Wolftrax and ask if you can go with him
outfit yourself and gear carrying bags to suit, and learn some spanish