Hey there.

If the lady does decide to ride her own bike, I would suggest the Yamaha XT660R. It’s a very good and durable bike that would take any terrain with ease, so they will have no problem completing their journey after the USA departs from them. The nice thing about the bike is that it’s got a good ground clearance of 210mm (8.2 inch) but still a relatively low seat height of 865mm (34 inch / 2.8 feet). So she will be able to reach the ground with no problem. The bike is also light with a wet weight of only 181kg (399 pounds). The Xl700v Transalp from Honda will be a bike to conceder for her as well seeing its seat height is 25mm (0.98 inch) lower than the xt’s. However it is much heavier weighing in at 191kg (421 pounds) dry weight.

If you are in the main menu of the hubb’s forum, and you scroll down almost to the bottom. You will fine a tread for woman only, it may be a good idée to ask them about a bike for the lady, and what will be the best option 1up or 2up for her.

If she wants to go 2 up the recommended BMW’s will be the best choice.

For the guys, if you have limited experience with big bike I’ll go for something in the 600 class. The XT660Z; KLR600; Transalp700 or maybe even the new 800GS depending on your cash situation are all good candidates to look at. I just think if you all ride on your own bike the smaller bikes will handle easier for you.
Hope you will get the right info you need and keep us updated about your trip