If you're just shooting for halibut, I think Nikikchik/Anchor Point is the way to go. Other than Yakutat, Cook Inlet has been the most consistent large halibut fishing I've had. A lot of times your trip is what the rest of the boat can handle. If you draw a crap straw and get put on a boat with a bunch of people that have no business being out there, then ya, it can be a quick gather one barely under and one barely over and be back to the launch by brunch. Try to buy the boat if you can, then its the trip you want and not decided by the old couple puking in the cabin! That goes for fishing out of any place. I fished with Captain Steve's out of Anchor Point last summer and their guides have daily bets for the largest halibut. And the way they fished reflected that. Just a heads up, everyone wants to catch big halibut until it's time to do big halibut stuff. You're in bigger and deeper water so you're fighting the tide for a 5-8 lb weight in 300 feet of water while trying to hold onto the side of the boat. It kinda sucks unless you're into it. My trip out of Homer was underwhelming and same with Seward but the difference is that those places have some better multi species opportunities.
To be fair, I've been trying to work in a trip with Crazy Ray's out of Whittier for a bit now. They have a good reputation but I don't first hand experience yet. So I have not fished out of Whittier but its high on my list.
If you're fishing the Kenai for Salmon in June, go mid week and go with a guide that leaves at 4 am. If you do an afternoon trip you will be trying to find a spot to fish within 50 boats already parked where you want to fish. I've floated the upper river numerous times in June and the water is very beat up. You can catch trout and its probably OK fishing, but I guess I just compare it to the fall when things are world class. Also realize "fly fishing" for sockeye isn't everyone's cup of tea. I love it, but a lot of people hate it. I was one of them for about 1-2 years until I got really good at it. An alternative is Kasilof kings, but as king fishing is, it can be very hit or miss.
I would skip Denali especially if you're going to the Peninsula. That adds two full days of driving and the park is underwhelming IMO unless you're driving your own rig during the September lottery. Unless you're really into smelly busses full of tourists, it's lame. If you want to drive north of Anchorage, take the trip to Matanuska Glacier and stay on the Glenn instead of Parks. Take walk around on the glacier - the ways things are going you may not have many chances left to essentially drive right up to one. The drive up the valley is awesome and its only a few hours max from Los Anchorage.
Also, remember that even though you're on vacation, there are still people trying to live and work through their normal day! Don't be the guy slowing everything down!
