Terry, you're so right about our selective memories. I too would have said, oh there's not much pavement at all on the Primitivo. But once I read your post, I then started thinking, and there are even more -- the walk up from the reservoir before Grandas has a rather long-ish road stretch, and from Ponte Ferreira to Melide is nearly all road. But there are mercifully some off-road breaks in between to keep our feet from complaining too much.
If off-road walking is the primary goal, I agree with Giorgio that the Camino de Madrid is probably the most "off-road" of any Camino I've walked. It is quite amazing how the amigos association was able to get people off the pavement so quickly -- even leaving Madrid, it's not more than a couple of kms before you are on paths.
In terms of hills, you'll not find too many, but the ascent to Fonfria from Cercedilla is a very nice one. The Camino de Madrid has excellent pilgrim infrastructure with two great albergues with resident hospitaler@s (In Puente duero and Villalon de Campos). Segovia is a great place to visit, and you can easily do a detour to visit Valladolid for a day, which is another really nice little city.
Buen camino, Laurie