Take the train
The most famous is Snowdon Mountain Railway which takes an almost vertical route to the summit.
The Ffestiniog & Welsh Highland Railways were both created originally to serve slate quarries, but are now firm favourites with Snowdonia holidaymakers.
The Ffestiniog goes from Porthmadog to Blaenau Ffestiniog, and, as you chuff chuff your way through 20 kms of Snowdonian sumptuousness, you can raise a glass of Purple Moose local ale or Welsh cider from the bar. It deserves a toast too, climbing from sea to summit through fields and forests, clinging on to the mountainside like an old mountain goat.
Equally delightful, Welsh Highland Railways run alongside the foot of Snowdon and the village of Beddgelert and on to Porthmadog. There is limited room for bikes on this service too, if booked in advance.
And for anyone nostalgic for Thomas the Tank, Talyllyn Railway is the narrow gauge that inspired the author. Resist the temptation to sing the head wrecking theme tune as you head down the line though.