We visited in July and purchased a combination ticket that included the Gondola ride to the Observation Deck and the Activity area with credit toward lunch at the Tamarack Lodge. The ride and views were worth the trip with really great views of the Lake from the Observation Deck, but there's no need to eat lunch at the Lodge.
At the top, the kids took advantage of the other ski lift (open chair lift to a higher point) (which was worth it) and the summer intertube ride (3 rides for $10) which was not. The ride was only about 2/3 of the length of the tubing surface as the kids would always slow down and stop well before the end.
Lunch was not good at all. Storms were threatening (which will close the Gondola), so there were not many people at the lodge. They started closing the food stations (salad bar etc) leaving few choices and fewer choices that were very good. Their BBQ Beef was dry and bland, the cornbread was the same. If the lodge had a view of the Lake, maybe this option would be more viable, but it has a view of the activity area that you can enjoy for free (or for less than a meal). Save your money, skip the combo ticket and find a better lunch back at the bottom of the mountain.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.