The WR250R as a overlander bike?

thats very good would be nice to see the kawasaki klx 250 in there

I have not done any 6,000 mile turnaround like some of the posters, but I ride long distances often in a high-temperature environment in the Mojave desert.  (Palm Springs to Las Vegas etc.)

Regarding the Honda 250: Really check out the bikes carefully and read the comparisons I think you will see which one to choose.  (Although the regular fuel is attractive)

Regarding the Alternator:  People are posting the alternator outputs like 350 watts is a great number.  What needs to be posted is the actual reserve capacity which takes test equipment to figure out.  A bike with a 300 watt alternator may be better than the the one putting out 350 watts because the 300 watt bike only takes 60 watts to keep it running and the other one take 150 watts.  The WR must do pretty well though, I see people putting a lot of grip heaters and warmers on their bikes, and those suck juice.  

Weight:  Check the weight ratings.  The WR carries almost 400 pounds stock.  You can take stuff with you.  That Honda comparison chart didn't even mention the load capacities.

My 2012 has over 21,000 miles in 18 months.  It has had one true failure, a stator/rectifier.  Otherwise, oil and filter changes, a new chain and sprockets, spark plugs, tubes and tires, air filter, grease, chain care.  Thats it.  I regularly wash it, clean the fork tubes each wash, and no fork problems.  I ride where there can be a lot of dust, when I get home I wash it and wipe down the tubes with a damp rag.      

Reading Big Dogs Adventures is what finally convinced me to buy this bike which many think is too small of a displacement machine for what you ask of it.  I have loved it, and use it every chance I get.  

You won't be able to pull 70 MPH uphill in a headwind, it is not that strong.  But it does 65-75 easy in normal riding and if you run at 3/4 throttle which will easily get you 65 mph, your gas mileage kicks butt.  The stock Bridgestone tires are ok for the dirt and that actually are very good on the highway, so much so, that because I often drive a long way on pavement to get to where I ride off-highway, I continue to buy them.  I don't like it at 70 mph with the butt end of the bike wiggling all over the place.

Seeing what I was doing with the bike, the sales guy that sold me the WR ended up buying one about 6 months later.  We now regularly ride in the surrounding deserts and mountains.  The dealer he worked at sold Honda, Suzuki, Kawasaki in addition to the Yamaha (and the WR costs more).  That says something right there.  

I hope you can post about the adventures of your trip either here or another forum.   Good luck with your purchase whatever you choose.

very good a lot of good info thank you for that

Re the fuel quality issue: I haven't had to run 91 RON yet, but those who have a WR and used it report no issues whatsoever. This may be a useage thing, since with the hours of slow running that we do at work, using 95, mine has pinged and rattled on several occasions until there is a chance to run it normally. Not surprising, not really an issue, and to be expected since it's well outside design parameters.
 
I think that at normal average engine speeds, 91 RON would probably be just fine to run in the WR. I had a WR426, which was 12:1 from memory. I rode it from Kalgoorlie to the Canning Stock Route and back, the Victorian high country, and a trip from Tibooburra to Marree and across the Simpson desert, all on 91 octane because that was all that was available then. It ran like a jet. Amazing. So our little bikes will more than likely do it, too.
 
As far as the coolant capacity statement by the Honda owner goes, I think that he is only partly right. So far, in extreme conditions, my WR temp light has steadfastly stayed off. Yes, it does work! So the engineering of the cooling system is the thing, not how much coolant is used imo.
 
Just as a matter of interest, and to back myself up I guess, the 660 Tenere's radiator and engine coolant capacity is 1.2L. The WR's is 0.9L. Both exclude expansion bottle volumes. The Tenere seems to be cooled well enough in very hot weather (>40degC) in spite of its statistical disadvantage. It certainly heats up my left leg, which the WR can't... Admittedly the specific output of the Tenere is less than the WR ie 78bhp/L vs 124bhp/L. Even so...