Sorry, can't help with the parking, but good luck with the Weisshorn. I came down the E ridge and by the time I reached Randa I really wished I'd spent the night at the Weisshorn hutte! 3100m of descent... aarrgghh!
Parkhaus Randa. 88 places and 12 CHF per day. In the very unlikely case that there's no space use one of the many car parks in Täsch and get the train down.
