I was in Birmingham for a day and my flight was from Manchester. As I had the whole morning free i decided instead to take the highway directly to drive throught the Valley via A6 road. First we drove to Derby, which is a very pleasant town and the ladies in Turist centre are very nice too :)
The valley itself starts immediately after the outskirts of town so if you drive to Matlock you should see all the mills. One mill is even in Derby. First on the road is in Darley Abbey - unfortunately we missed that as there was no sign for that in advance. In Belper the sign is good - you can park next of the mill. Opening hours are only from 1pm so i had no possibility to go in. Mill is placed in a romantic country surrounded by the river and gardens. I can imagine i could spend there some nice evening with my girlfriend :) We missed Cromford mill which is some miles north as it is not on the main road but near of it is the Masson Mill. I was quite surprised when i saw there is a shopping mall and a parking house inside. At least there is a museum. As we were in a hurry i was not able to enjoy the whole place, but i'd like to go back as the country is beautiful around the river and the history is around you - as the area looks like you havent moved away from 19th century. There are some guides for walks and i believe it is worth to take a nice walk.