Yep, that's pretty much the route. You don't actually have to go on the road near the reservoir as the footpath continues across the fields. I've got the route in my handheld GPS.
I've just spotted that about a walk mile from the Viaduct is Ardingly Reservoir, complete with a giant plug hole thing that is crying out to be illuminated at night!
Black Rock is indeed the car park next to the nudist beach. Sadly the mini-train won't be running so it's either walk, (I've done it before and it's quite a nice stroll along the sea front), or take a bus which will be £2.20 each way, (ask for a CentreFare), which you can pay for with a...
Driving in central Brighton is horrendous and it will be worse this weekend as trains have been cancelled and it's also half term. So I suggest we park at either Black Rock Car Park, about a mile and a half to the East of the pier, (BN2 1DZ), or at Brighton Marina, (BN2 5UT), which is another...
Sorry for the late reply, it's been an 'interesting' few days... (Not in a good way). Right, the 23rd is doable for me, and possibly the 16th at a push.
I shall be away working in Mexico so can't make this one. You all need to buy one of these light suits and walk along the South Downs Way at night wearing them!
https://glowyzoey.com/collections/led-stick-figure-costumes
Sadly mine is poorly as I decided to replace the switch and in doing so managed to kill one of the LEDs. It's in the 'to do' pile, but it's been there for at least 18 months...