Snowdon (Yr Wyddfa) is a good mountain. There are lots of paths to choose from, from steady grinding walks to very hairy ridge walks. On a clear day (something of a rarity) the views are well worth the effort. I've never done the train, but that isn't meant as any form of criticism, it is what it is. (The one path I haven't walked is the long path up by the railway from Llanberis, just don't fancy it somehow.)
I can remember grinding up the Pyg Track in the 70's thinking of a nice cold pint in what was then the old Café on top, only to find the bar was closed (it was a Sunday
.) I nearly ran amok !!! ... fortunately the Welsh wised up and did away with that nonsense.