I don't have any experience out of Valdez, but I've spent several summers chartering/guiding out of Whittier and grew up doing boat based bear hunts around the peninsula. I'm not trying to scare you out of the trip, but I would be very careful with your first trip on the salt being an overnighter in the sound. While there's a lot of places to tuck away and hide from the weather, there's just as many spots that can catch you with your pants around your ankles and blow up in a hurry. Port Wells is a big one, many times I've came out of passage canal in 10 & 2's, just to have the wind switch on us halfway across and turn into 5-7 footers that made turning around in them sketchy for our 42' charter boat. Every year there's multiple boats that go down, often resulting in deaths due to people getting caught in the wrong place at the wrong time, or pushing the limits to try to get home instead of hunkering down for a day or two to let the weather pass.
Bring plenty of fuel, food, and water with you in case you need to stay out an extra couple days, or have to take a longer route home to stay safe. Your boat is capable of doing it size wise, but if you don't have twin motors I would take that into consideration when planning as you're out of luck if you have one go down. It sounds like you have experience in big water. The biggest difference you'll run into in the sound weather wise is the constantly changing local currents and glacial winds. Tide levels come into play more for exploring smaller bays/entrances, and beach access during a stalk when you find a bear to go after.
The silver lining with the sound being so popular is that there's more people out there to help you if you get into trouble, and don't be afraid to ask for it before it's too late. I would definitely recommend getting a SeaTow membership for the season, it's cheap insurance in case you have engine trouble, find a rock, or get hung up in a bowpicker net. If you see a bowpicker (30 ft. boat with a cab in the back and open front deck), steer clear of it and keep an eye out for any buoys withing a few hundred yards of them. If you manage to run between them and the end of their net, not only will you severely mess up your prop/lower unit, but you'll have a pissed off Russian screaming at you while you're dead in the water. You shouldn't see many of them that early in the year, but if you go back out in the summer time you'll run into dozens if not hundreds of them.
For the hunting side of things, one big lesson that you'll learn quick is just because you see a bear, doesn't mean you can safely get to it. Most of the area's coast is steep and rocky, and can get dangerous quick in a zodiac. Before you go after a bear, make sure that you're in a spot that has a safe spot to pull into with your zodiac, and that both your landing spot and your main boat are protected in case the wind switches up while you're on shore. There's plenty of bears to go around, and they're constantly moving in and out of cover so don't feel discouraged if you're around other boats. There's definitely some etiquette involved in staying out of the immediate area when there's already a boat there, but I've shot several bears within half an hour after passing another boat that's leaving the bay as we were heading in.
