Just to let you know from our experience, we saw more wildlife in late August than in early July. We've been on two Alaskan cruises and we did see a two bears on the shore line as our ship was passing by northern British Columbia, when we went the first time in July.
But when we went a couple years later in late August we saw a mother bear feeding her twin cubs salmon, just off the walkway at the Mendenhall glacier in Juneau. It was awesome. She was partly hidden behind some bushes but every once in a while you could see her and the little ones. The salmon are so thick in the streams in August.
As others have said, the tours do offer the best chances at seeing the animals.