OK. Got back just before 7pm after riding the original route suggested:
Leith -> Roseburn -> Dalmeny -> Kirkliston [on the railway] -> Newbridge (on the road) -> Boathouse (canal) -> Blackford.
I was going to ride under the canal and in the A71 or A70 as suggested, but curiosity got the better of me and I bumped up onto the canal to see what it would be like!
http://connect.garmin.com/activity/69912768
2 hours for 25 miles, which is good considering I spent 40 minutes averaging 8-10 on the rough bits.
So, for those who'd appreciate an up-to-date status on all of the above (if not, don't bother as there's nothing exciting).
- the closure en-route to Dalmeny is quite annoying going west, because you have to shut down this entire traffic stream while riding uphill along the roadworks. Bet there is a lot of aggro here, although the car behind was quite agreeable about it. (Helps to be on the right sort of bike).
-They are making the pavement very wide - I can't see how any sort of lane would fit on-road which is unfortunate, but if it ends up as wide as it looks, I might ride on it. It looks like they're taking away half the east-bound lane, for reference.
- The railway between South Queensferry and Kirkliston seems to have a random gap in it, protected by Sabretooth Tiger Death Ray Security !!!! . Strange - a paved path under my old commute clearly heads south, but there is no such path where you try to join it from Dalmeny village - you have to ride a few hundred meters on and bump over the grass to reach the embankment.
- Once on the embankment, I realised it was basically just soft ground 85% of the time, with no sort of surfacing whatsoever. While navigable on one inch slicks, it is pathetically slow and you're paralleling an actual road (even if it is a boy racer paradise road) which would be 2.5x as fast.
- From Kirkliston to Newbridge I rode on the rat run, not that much fun but it only took 2:45 to cover the mile, it is smooth and the terrain is agreeably flat. Not somewhere you'd take your kids maybe.
- The canal from Newbridge to where the paving starts is 3.7 miles and I rode it at around 10mph without much hassle, would have been considerably faster on big squashies though!
- From the paving to my exit was 4.7 miles ridden at 15mph (taking it very easy). I passed one rider coming the other way and let one overtake me when I stopped for directions. Unfortunately he was both slower than me on the clear bits and much faster round the bridges, live and learn.
- the narrow viaduct is *VERY* scary. God knows why they have not surfaced it - it took a good bit of nerve to ride with the front end of the bike jeaping up in the air and not enough speed to have easy steering way. Might be bent-specific, since I remember zipping across this on the fixed wheel.