Edinburgh - Glasgow. The most interesting ride ?

[toroddf]

What is the most interesting ride between Edinburgh and Glasgow ? Let's for the sake of the argument say a max 75 miles ride between Edinburgh Waverly and Glasgow George Square.

With interesting, I mean with the middle part not as trafficky as the start and the end of the ride. And yes, I know the canal is probably the less trafficky and easiest one. But I want some solid tarmac under my thin wheels.
I have done A70 and parts of A89, B7066 (over Blackburn) and A803 (over Kilsyth). Any better suggestions or any hidden gemstone hidden among the gravel out there ?

Suggestions ?

 

[HLaB]

You'll be struggling to get 75 miles in without a big diversion but I like the wee villages along the way like Shieldhill, Slamanan, California (yes its really a Scottish Village). Coming out Edinburgh via Crammond Brig/ Kirkliston you can easily get to the quiet roads through the villages by cutting down south at Winchburgh and heading west to Torphichen, Avonbridge and Slamanan or stay on the Linlithgow road (B9080) and head west through Maddiston, California and Shieldhill and then Slamannan.