Routing on forest roads using OS overlay.

Hi everyone.  

Is there a way I can plan a route using forest roads that appear on the OS overlay that don't appear on the cycle.travel map overlay?

I am finding the OS overlay really useful but I can't always take advantage of the additional detail when planning routes.  For example there's a forest road west of the the Falls of Shin in Scotland (57.9603,-4.408) that I can add to my route, but the roads in the Linsidemore Wood, just  to the west (57.9609,-4.4795), don't appear on the cycle.travel map and are ignored with the route continuing along the A837.

Please forgive me if I'm missing something simple or misunderstanding how I should be using routing .

Many thanks, Richard. 

Black Mountains 1 MTB

Rough Ride Guide/MBR Black Mountains "hard route"

48k, Starting in Talybont on Usk and loops to the North East of the village

Hemyock - Stockland rtn

Minor roads from Hemyock to Stockland via Churchinford.  3 climbs of 10% or more with a max of 12.8%