We did Snowdon on the weekend – started at 6am – we were back off the hill by 9.25 and we had to stop for about 15-20 mins to let a marathon with 800 people come up telegraph valley (didn’t anticipate that!).
Without that I think we have done it in about 3 hours – starting at the car park in Llanberis and going up that path and coming down the Ranger.
The top was surprisingly busy with walkers when we got there about 8.50 but on the way up we didn’t hold anyone up / get held up by anyone.
The first bit of the climb is on a tarmac road which took about 15 mins ish I would say. So you could get going a bit early and hit the actual voluntary bike ban area bang on 6 and be at the top by 7.30-7.40 ish. I reckon you could then get down before it gets dark, but I’d take lights just in case.
Not sure if anyone would tell you off or not if you were on the actual mountain early – most people were just stunned we’d biked up / down it given they’d found it quite a tough hike in all their gear and with 2 walking poles each lol.
Few tuts right at the top for no apparent reason – we were outside the curfew and were really courteous to everyone we met. I stopped to let people past in narrow bits and did my best to enhance the reputation of mtb-ers.