Can't say about Seward, but in general any rockfish hotsot I've seen isn't hot for long. Doesn't take many boat visits, certainly less than a season, for it to turn into skinny fishing. As you indicate, they're great fish because they're easy for kids to catch, but they're their own worst enemies.
Not putting your request down by any means, but making that a preamble for an alternative suggestion.
Hottest and best fishing we've found for kids is sole or flounder. Put a 1 oz jig on their typical "trout" spinning rods, add a little sliver of bait to the hook, and make little bounces on the bottom. If you hit the beds of rock sole on gravel bottom or starry flounder off river mouths, you'll have more action than you've ever heard of with rockfish. And great eats too, once you learn how to fillet them.
look for any rockpile around 60-40 feet, usually around the points of any of the islands around the entrance of the bay. We found three nice outcroupings this morning and my four kids had a blast catching limits of blackies and copper backs. My youngest caught the biggest blackie I've ever seen in 35 feet around Cheval.
If you're boat is big enough and the water calm enough to get out of the bay you're likely have better success in areas that don't see as much boat traffic. Fish points of the tips of islands, peninsulas and mouths of bays in 30-75' of water. Try different spots if you're not successful, but looks for spots that get good tide and current action and that the charts indicate are rocky.