Go ahead and book it, you won't regret it.
The " Denali '' area is the very hearth of the Alaska that most visitors want to see up close. Generally, the typical tour has guests staying 2 nights in Denali Park, and one of the two days there involve a wildlife 8 hours tour right in the Park; splendid.
Hotel accomodations are quite cosy and picturesque; scenery is superb; and, remember, you're with Radisson....just as good an outfit as there ever was to take good care of you.
Past waves and happy memories: SUMMIT, MERCURY,DAWN PRINCESS, ISLAND PRINCESS X 2, REGAL PRINCESS.
Nest up: CENTURY June'08....B2B Norwegian Fjords/Artic/NorthCape & Scandinavia/Russia
Yes, it's worth taking but I recommend it pre-cruise, not after. Follow a week on a lovely Radisson ship it's quite a jolt to hop on and off buses, check in and out of hotels. If you can take this pre-cruise, you'll really appreciate the ease of cruising.
The only problem with Denali is the mountain has its own weather system. I was there for three days, cloudless skies, and never saw it because of the fog at the top of the mountain. But there is wonderful game viewing around the area. I'd go again in a heartbeat!