FWIW, I second exploring the recumbent option, especially if you happen to have the financial wherewithal.
It's my understanding that internal hubs are more common on recumbents than diamond-frame bikes. Also, I'd expect that if you get a trike, you can pile on the pounds with less of an impact on handling or drag. The position may also benefit your back.
Also, it looks like most of the places you'll be going are flat, so you'll get the full aero benefit of the recumbent.