I rode from Hebden Bridge in West Yorkshire to my mum's house in NW Coventry in 2007 and have a route plotted which avoids busy roads as much as possible. I went close to Ashbourne without actually going into it.
Have you got a GPS system for your bike? Without GPS, you'd probably find it difficult to navigate because of all the quiet little lanes I used. I have a GPX file which would help you. Tell you what, I'll stick it on Bikely later.
Here's a list of the places I went through/by which you can see on the OS Landranger maps:
Keresley, Corley, Fillongley, Wood End (not THAT Wood End!!!), Gun Hill, Old Arley, Church End, Charity Farm, Broomfield Farm, Bentley Common, Baddesley Endsor, Grendon, Polesworth, under M42 to Shuttington, Seckington, Thorpe Constantine, Clifton Campville, Lullington, Coton-in-the-Elms, Walton-on-Trent (annoying singletrack bridge there - avoid at busy times!), Barton-under-Needwood, Tatenhill, Rough Hay, Anslow, Rolleston-on-Dove, Marston-on-Dove, Hatton House, Mount Pleasant, Bartonfields, Longford...
From there I skirted round Ashbourne, but since you want to go to it, you could go:
Alkmonton, Yeaveley, Wyaston, Spitalhill, Ashbourne.
Total from Keresley about 80 km (50 miles).
If you want quiet roads - there's your route; if you want the quickest route, that isn't it!
Sorry, I couldn't give you a more detailed reply - I'm busy!
