I've got a 2007 WR250F and would certainly agree they are awesome offroad bikes. The tank capacity is fine for 70-100 miles offroading but should stretch to 120+ on the road I believe. Of course, that is a bit slim for serious overlanding but you can get big Acerbis tanks that would cure that problem. The other issue that can be cured is the seat, which is narrow and hard and literally agony after less than an hour. OK for day trips green laning but would absolutely have to be changed if you plan to spend all day on it. It's also quite high but that's just the price you pay for a bike with good offroad capabilities.

I haven't done any heavy mileage on mine but I'd be a bit reluctant for a couple of reasons. Firstly a 250 with the best will in the world is going to struggle on an open road with a load of luggage. They aren't designed for continuous high speed use and I would be concerned about longevity. Secondly the sump only holds just over a litre of oil so this is being worked very hard and if it does burn any you'll run out very quickly. Anyhoo I wouldn't rule one out, there is no 'perfect' RTW bike, they all have pros and cons and the WR is no exception.

Saying that somebody'll probably come along next with stories of how he's been round the world 3 times on one towing a trailer without an oil change