As much as I liked my diesel 2500, they definately are not the best vehicle in the snow. I had a toyota truck (predecessor of the tacoma) and put 100k on it up here, roughly 1/2 in winter driving conditions. I ran a/t tires year round and never had problems in the winter and could drive mostly in 2wd. When I got the ram 2500, the factory tires were terrible in the winter and I think I got stuck three times that first winter. After a terrifying incident on ice I got studded winter tires and they were much better, but I still had to use 4wd fairly frequently.
Definitely go with a dedicated winter tire with a full size diesel truck. You need all the help you can get.
