I don't have a Nomad, but have pulled a Burley Solo child trailer for lots of miles and have been really pleased with it. From what I've seen, the Nomad is basically the Solo trailer but with a cargo setup. The Burley is very high-quality and pulls really nicely. I do agree that a two-wheel trailer is not a good choice for anything but roads and well-maintained paths. It would be fine for the GAP, but miserable on the C&O. I say this from experience, having done a short tour with our Burley behind our loaded tandem on the C&O. Since the C&O is usually a double-track, one wheel was always dragging in the middle of the trail.

As an aside, I rode the GAP one-way over a three-day Columbus-day weekend without much problem. Actually, it really only took about 2.5 days, and I had plenty of time to stop and smell the roses and take photos. I'm not a big mileage guy, but it was perfectly doable. My longest day was 63 miles, with two other 48 mile days. My trip journal is at http://www.crazyguyonabike.com/doc/BrianGAPtour