Figured I'd ask this here, given the experience of those with trikes or trailers will likely match up.
I'll be giving my Spokes map to my friend with the handcycle*, and we're meeting up at the Shore for dinner next week specifically because he can easily-ish get onto the NEPN with a big loop to get there. But he wants to explore more. As off-road networky, or very quiet roads, as possible, given his relative uphill speed to traffic, and still finding his feet (if you'll pardon the pun) with the handcycle (he managed to crash a borrowed one on Cumbrae a couple of weeks ago and bashed up his already-mobility-limiting ankle).
So where are there barriers and so on that will definitely make it too troublesome to ride?
* he's now got two - the monster MTB, which felt very odd, and a new road bike, which he lies back on about 2 inches off the ground. He's started doing Arthur's Seat laps on a Sunday (when the road is closed) to build up the arm muscles, and we compared Strava times - we're perfectly matched on the downhills, but the up sounds like a heck of a drag, taking ten minutes more!