Ten of us did this last Saturday. Absolutely fantastic experience. Set off shortly after 4am which is absolutely the best time to ride through Preston and Lancaster on the A6 if you really must use said road. It's lit all the way through that section, though minimally in places.
Dark for the first couple of hours and wet roads with intermittent drizzle for all of Lancashire and half of Cumbria. Diverted off the A6 at Milnthorpe to avoid the dual carriageway run into Kendal. There's a signed NCN alternative which has some interesting lanes but is all (just about) tarmacced.
Brekkie in Kendal McDonalds then over Shap (couple of steep-ish ramps but nothing too serious) and down into Penrith as the weather brightened up, and on some nice rolling roads with not too much traffic into Carlisle. Bit of traffic to negotiate here then got a draft off a tractor for a couple of miles along the A7. Sadly he turned off well before Longtown.
More food at the Bakery/Cafe here (1st choice tearoom was shut for holidays but this was a more than acceptable alternative). Off the A7 and into Gretna for the obligatory photo opportunity before pressing on up the marvellous B7076 for Moffat. Quick pitstop at the ice cream and sweeties shop before getting back on the road and making for the Beeftub.
If you've never ridden the Devil's Beeftub on the A701 out of Moffat you really must go and do it. Unless you're one of those strange hill-hating cyclists you will love it. It's like the perfect climb. Very long and gets you up quite high but with a steady gradient and never steep. Awesome views to the side and behind you. Fairly wide road, not much traffic, mostly reasonable surface. Shame about the headwind on the descent but you can't have everything.
More fuel required but unfortunately Laurel Bank tearooms in Broughton shut for refurbishment by new owners. Luckily village shop well-stocked with sweet items, had a coffee machine, and was still open when we arrived.
On down the A701 with an unwelcome climb (at this stage in the ride) as it leaves the River Tweed behind. Through Blyth Bridge and Romanno Bridge then hang a left for West Linton on a lane with a much better surface than the A-road we've left behind. Look out for Deanfoot Road on the right in the centre of the village, then another right on what looks like only a housing estate to stay on Deanfoot Road.
Another fantastic stretch of tarmac. The headwind had cleared off somewhere else by now and we flew down the super lane, belying the 180 miles in our legs. Great views to the Pentlands on our left and Moorfoots (?) on the right, even the odd glimpse of the Lomond Hills ahead letting us know our destination could not be far away.
Through Penicuik without incident, down past IKEA and under the bypass (I'd been worried about this roundabout but no problems). Headed across theough Gilmerton and past Danderhall, down the Wisp then onto the Innocent Railway. Far preferable to the direct route into town plus we needed a little loop around to ensure we registered over 200 miles for the day!
The tourist option had been requested by my clubmates so we sped down through the park between parliament and palace before crashing down the gears and slithering up a soaking wet Royal Mile. We'd missed the rain but not it's after-effects. Quick photo at the Castle (thanks car park bouncers) and then very carefully down the Mound and another pic at the Postbox. Celebratory beer at Milnes. Great day!