IMHO, dyno hubs are definitely worth it for commuting. But since you're talking about touring, I don't have a strong opinion.

I usually quit before sundown, so, like Derailed, I don't do much touring after dark. There may be some plugs at restaurants or libraries, or they may be taken or unaccessible.

I question whether you'll be able to keep both a GPS and a phone charged with a hub. OTOH, if your alternate solution is to recharge at a motel, the hub might pay for itself within a week or two.

So think hard and let us know what you decide!