If you’re on a normal (non e-bike) the quickest routes back up are quite brutal.
I normally park in the main Cwmcarn car park and pedal up the tarmac Forest drive but then cut off and follow the fireroad to the start of airstream 2 on Twrch. I follow that to the steep concrete ramp then go up the tarmac from there to the off piste. I find that’s a nice warmup before hitting the steeper stuff. Equally you can go all the way to the off piste on the tarmac if you want to do that.
You can ride it a bit like a non uplifted BPW for a smaller climb – sessioning the top halves to the fireroad and then back up. Then sessioning the bottom halves seperately.
The top half has a steep ish push up at the Wacko end – it goes out of a clearing on the fireroad where some rock has been carved out – did you find that?
From the bottom you can either pedal along and up Darran Road (I’ve not tried this but I think it literally goes straight up the hill), there’s an off road way back up which is also quite hard going – I can pedal most of it but there are a few steeper / loose bits. Or you can pedal along the canal, back up to the Cwmcarn car park and then back up Forest drive.
We did a day of it early 2023 – ended up being about 30km and just shy of 1500m of climbing. I was broken after that, but it was a great day.