I know you said not to use the map to follow roads, but I will offer you an unsolicited piece of advice in case you are planning to take PA 32: Be careful. There is no shoulder and impatient drivers can be dangerous depending on the time of year and traffic volume. Last year I got buzzed by a couple of people when the road wasn't even crowded. The NJ side is better, so definitely cross over at Frenchtown. Once you pass Milford, NJ, the road is really cool until Philipsburg (total pit town) and usually pretty empty. At some points, it's less than two lanes wide. If it were me, I would go into New Hope, cross into Lambertville, NJ (or at least Stockton) and take the canal path to Frenchtown. The parallel Rte. 29 in NJ has no shoulder until about 1 mile north of Stockton, where it widens and has a great shoulder. The canal path is wooded and the surface is, in most places, good enough for even skinny tires.
Send me a PM if you would like more info.
PA Rtes. 113 and 313 will also likely be extremely busy. PA 23, at least as far east as Elverson, is another part I would avoid if all possible. The valley roads between U.S. 322 and Morgantown and much nicer.