Riding in wet and snow = disc brakes. The Meks forks have disc brake mounts. The best price on Meks forks I know of is on eBay, Hooier Bicycle Supply, search on Meks 26.

General rule. If you wrench, get the cheapest version of the frame you like, since your replacement parts can easily surpass the high end of Dahon. If you don't wrench, buy the closest fit to your needs from Dahon. I don't know the max tire size.