Tim,
There are grizzlies in Denali - you can usually see them from the buses that take you into the park. We saw only one, but it came right over the road fairly close to our bus (it walked right in front of another bus).
The place to go for grizzly viewing is Katmai National Park, specifically Brooks Lodge. Late June to early July is the prime time to see the grizzlies catch salmon at the waterfall. I was there late August and early September - the bears are still active, just not at the top of the waterfall, since the salmon have weakened and are not jumping anymore.
Brooks has limited facilities and usually books up at least a year in advance. Established groups typically set reservations several years in advance, so that would be an option for gettng there. The typical way to get there is to fly into King Salmon, AK and then take a float plane to Brooks. You do need to be careful, because there are no barriers between you and the bears except for common sense. On our last evening near our cabin, I ended up about 30 feet from a grizzly who climbed up the hill. That was a little too close for comfort!!
Ovearll, it was an amazing experience I will never forget. There are observation platforms and there is almost no way you can go there and not come away with some incredible pictures. Definitely worth it if you can get there.
For seeing orcas, we saw 2 pods around the Resurrrection Bay area (near Seward). Also saw stellar sea lions, puffins, bald eagles, etc. We did a tour with Natural Habitat Adventures who do a great job (
www.nathab.com).
Mark
