Roger it's not as bad as people make out, if you've done the correct training and get your pacing right then it's more than manageable. Your time will be slower but it's not one that's run for fast times.
Snowdon ranger is just before 18 miles good spec point. I can't answer the real ale question obviously, I'm an athlete
Yes I would imagine so Katherine, although parking in Llanberis may be a bit of an issue ie he may have to park a bit away and walk in but the roads are open there to get back into Llanberis. I have watched at Rhudd Ddu (just after the climb out of Beddgelert) the last couple of years and then driven onto the foot of Waunfawr then driven into Llanberis so seeing runners three times.