Well there is another way.

I see you are shipping to the USA so you have a bike now. If not you may be able to buy used in the USA and ride it there then sell it used loosing little on the trip. Or ship it home import and sell there. I have not priced shipping for some time but it was going fore $800 to $1000 each way last I looked. It may prove a better deal to not use your bike and "save it" for the rest of the trip. You can easy put 20,000 miles or 32,000 kilometers on the bike on that trip in the Americas. A sport tour will do well if you are gust looking to laying down miles. Most mid states are good to give a pass on. You will want watch the temp in the south and south west it can get hot.
You can do Mexico to Panama with out much problem as you are right there.

If it was me I look in to renting in Asia as getting you bike in and out may prove a bit much. A smaller bike is well made for the riding you will be doing there any way. But 2 up may not work well.


Now for the Qs

1) A small bike can ride the world a 50cc has done it with some one with no little time riding. I like a smaller 650 but I need the speed for freeways.
2) Honda or not unless that bike is sold in the place you are going and selling a lot you are still going to be shipping parts and hope the repair man knows how to fix it. Better bring a repair book with you.
3)Yes. BMW big and a price to match. But if you must go 2 up it still may prove a good idea. Others are in the running and if look at the rider storys you will see may others. Thing is about the size you do not feel it at speed. Not till you slow down 100 miles from any help and drop it on your leg oh then you feel it.

MPG is grate with small bike and still not bad on big ones I like to get 300 miles on a tank. I also do not pass may gas stops in the more remote areas. Get a little jerry can to get pass any big spans. Pushing a over loaded overland bike in 100f, 38c only looks fun.

As others have posted 2 up has it down sides. Less you can take, if the bike brakes no one to send for help, no way to get way from each other and on and on. In the least you need to be able to pick up the bike and hope you can with all the gear on it. Can Emma and you get it up? how bout if one of you get hurt? I have a problems with 650 if it is loaded up that big BMW R falls I will need to repack it.

You may want to see If you can pack all the gear you want to take with you on the bike. Get a tarp lay out your gear and look to see if there is any way to get that on a bike. You may want to see how much you and the gear is and how much your bike can take. This in not going be like a short ride around a track on a bike that is little more hefty than you are That bike can be way over the load limit. Think pregnant rhino less jet fighter.

You want to get the DVDs and get to meeting.