We did some long-distance travel in our '65 Safari and thought we would need a generator, but decided to wait and see how it was when we were on the road. Didn't miss it at all- get a good battery (we switched over to a 4D from Batteries Plus), and if you are driving for a couple of hours every few days, the alternator in the tow vehicle will replace all the power you used. Don't get a generator just for coffee- switch over to a stovetop percolator or a drip-through "Thai/vietnamese coffee maker", which you can get at most asian grocery stores. We didn't sit around and carefully count amp-hours, we just turned things off when we weren't using them, and never ran low-ever.
I guess you could do the research, and decide the exact model and make of generator you would buy, and then if you end up needing it, go out and get it. I just never need another engine to take care of in my life.