For learning, go to Craigslist and check out the 250-400 class bikes. Avoid the real cherry ones as she'll probably be adding some rash to the bike.

Smaller bikes are less intimidating, are lighter and used ones are cheaper in case she decides to chuck the whole idea or quickly wants something a wee bit bigger. I'll suggest the Suzuki TU-250 and the Yamaha TW-200.
The newer Moto Guzzi V7's have optional lower seats, are light, shaft drive (one less thing to worry about), air cooled (at one point most engine failures are a direct result of a failure of the cooling system), light (at least 80lbs less than the Bonnie); but I'm a bit biased.
For two up touring a buddy just got a Victory Vision (her choice, not his) but the world is your oyster here with tons of choices ranging from older cherry Honda Goldwings (Aspencades are da bomb!) to modern wonders. And their prices! By the way, the new Moto Guzzi California Touring is very price competitive, not as big as the Vision or Indian while still fun in the twisty bits. Worth a look. A breakfast buddy has one and I keep thinking up lame reasons not to get one.
I think the CB could be made into a very competent tourer with dual Laam Seat (or Russell Daylong, Sargent etc. - keep in mind some of these seats will make the bike look ugly but your bum very happy) and a good windscreen.