WR250 or DR650.
You can't rely on mail delivered items. They are last resorts and often tie you up for weeks (if not months) on end.
Any bike will have to built for the ride. I did a 24000 KM, 4 month trip through Latin America on a XR650R. No complaints and I'm thinking about taking it to South America next. 50+MPG, and more then enough power.
And for God sakes, don't consider a bike by how much it can carry. Use the smaller carrying ability to widdle down all the crap you don't need and want to take. WAY too many people, especailly those with monstrosity of bikes take everything under the sun and it only hinders nearly every aspect of the ride. I had about 65-70lbs of gear, spare parts, tools, first aid, laptop etc. I will reduce my weight further next trip (offset it slightly with a warmer sleeping bag and sleeping pad)