I would suggest that if you do not have three days, you stay on the blue roads. If you are starting from the south, hit the visitor near the southern terminus for the book. I do not recall what it cost, but you want it. (You actually want it before you start, but that could be tough to do.)
Well, I backed off this page for a moment to find it. It is 17$ (ISBN: 978-0-89732-925-5) I didn't have this book for our first run because we ran north to south and there was no place to buy it at the north end. Even having run the trace as much as I have, I still get this book out as soon as the topic comes up.
We have run the Trace 3 or 4 times (I really don't recall and I don't have the coach's log book right here and it is Cold between here and there), and it is always great. Of those runs, on one we were the lead of the coach caravan.
There is literally an historical marker every other mile. With the book inhand you can decide if you choose to stop. Some are big things like the Mount Locust stop is not to be missed. Others are just a plaque that you can read in the book.
Get the map at the visitor center (you can download and print it too) and look for the actual trace as you drive. If you are there in the spring or fall and the trees aren't full, you can see a lot more. Mid-season, I have been told it is like driving through a tunnel of trees, but we have never been there then.
What ever you decide, enjoy the journey.
Matt
Matt & Mary Colie
A sailor, his bride and their black dogs (one dear dog is waiting for us at the bridge) going to see some dry places that have Geocaches in a coach made the year we married.