just noticed that they’ve updated their system and now include “osm” (open street map i think) maps which include paths and path-path-finding (ehe) – it’s not entirely straight forward, you have to be careful where you click along your route, as it usually finds the “best” (quickest) rather than the one you might want to take, but as an example here’s one we did the other day (well roughly, i don’t know these paths too well, it’s from memory)
http://ridewithgps.com/routes/530417
select “osm cycle” from the map drop down top right
very cool! i’ve used it for road rides for ages, looks like it’s great for off too..