Hi,
We stayed at the Sequoia a couple of weeks ago and were happy with it. We were in one of the lodges seperate from the main building, but although it meant wrapping up to walk to breakfast, we were lucky that we had fresh frosty mornings and it was a lovely wander through the woody paths to get there. So don't be too upset if you are not in a Montana room. The rooms are identical other than the Montana rooms being in the main building and having a mini-bar.
I also agree that the walk around the lake, through Disney Village to the parks is lovely. We had no interest in getting the shuttle as it's just as quick to walk!
The only other thing I'd say is try to book your breakfast slot for before 8.30am if you can. From 8.30 onwards it starts to get busy and from 9am it's mobbed. If you arrive after 8.30 you will need to queue for a table even if you are booked, so it's worth getting up a bit early and just enjoying the surrounding area each morning before setting off for the park. Book your breakfast slot at reception.
I'm sure you'll enjoy it.