It's quite a ways. I like to walk, too, but I probably wouldn't feel like walking that distance with all the walking I do in the parks. I bet it would take at least 30-35 minutes from the Disneyland exit to the hotel to walk, maybe more.
We stay there almost every trip- personally, I wouldn't walk it, it's pretty far. They have an ART shuttle that stops just outside that's usually pretty quick
It's a nice hotel and as you probably know the breakfasts are great! We enjoy being able to go back to hotel and have a bite to eat or a drink if we need it
I wouldn't try to walk it. The blocks are very long and there is a lot of traffic from point A to point B. The above poster is correct there is a shuttle but we ended up driving instead of the crowded shuttle.