I am finding this less fascinating as I go along. Back roads in the daytime start to look as alike as interstates after dark after awhile, except where they turn into Class VI roads and become undercarriage nemeses. I have long been fascinated by looking at road maps and trying my hand at getting places a new way, or exploring an area I am staying in for a few days.
Google maps at least indicates with vague shading when a road might be substandard; mapquest does not. Delorme gazetteers, which burned me years ago with Old Antrim Rd, almost suckered me in with Rabbit Hollow Rd.
Yes, I should be immediately suspicious of anything named "Rabbit Hollow Rd," but in NH, such things can still be the best road between two points.
You can tell an old road by the aged trees coming right up to the side of it, and in New Hampshire, by the stone walls on both sides. The moss and lichen on the stones are an additional clue, if you need one. I found that both Rabbit Hollow Rd and Talbot Hill Rd were prime thoroughfares a hundred years ago.
I also went through the Franconia Range, which is nowhere near Franconia - which has actual mountains - and Scotland, NH, which is clearly still swamp Yankee territory two hundred and fifty years after its founding by those Scots-Irish who also settled Appalachia. (And you can tell.) All this to find a back way to Rte 78, a Massachusetts highway that creeps over the border to end ingloriously in NH. I had never been on it. I doubt I'll need to see more of it.