The DSF is dead center of Hollywood Blvd. On a good day with no traffic, it'll be a 45 minute drive from Disneyland. On a not-good day with alot of traffic, it could take you up to 2 hours. Generally, Saturday is a poor day to drive into Los Angeles: it's got to be one of the worst commutes in the country. But as a late morning or early afternoon trip on a weekday, it's pretty easy.
Personally, I think if there are some current pins you're interested in, it's probably worth the trip. You can find a large assortment of previous LE pins as well, since many don't sell out. Great way to beef up your collection for trading if you've got some money to drop. It's also a great chance to check out Hollywood, grab a memorable bite to eat at a good restaurant, and see some sights. If you're not interested in Hollywood, though, and there aren't specific pins you're interested in, you may as well skip it - especially if you're only in town for a couple days.
It depends on your interest level in specific pins, and whether or not you're pressed for time.
-JD