First, I'm glad you’re headed up this way. The one thing I can say about late June and early July is that it's completely unpredictable. The weather can be nasty, or it can be good! The crowds follow the weather. Over the past 5 years, there has been snow and or cold, cold rain that time of year.
That said, it also can be very nice. You will want to plan to photograph from the east side of the park - Many glacier, St. Mary’s, Two Medicine, etc in the morning, and the west side in the evenings. There likely will be few flowers up high on Logan pass, but there will be a lot of snow, and nice waterfalls. You will find wildlife around Logan that time of year too, if you can see once you’re up there. If it’s snowing or raining it will be difficult. Plan to hit the Cedars and lake McDonald area if the weather is bad. I would concentrate on photographing the middle elevations. Tell me more about what you like to photograph and I can add more.
Keep in mind that weather offers opportunities but also can wreck your plans, so just come with an open mind, and a variety of cloths. Every time the weather throws me a curve, I end up capturing some of my most memorable images. You have to really focus on your photography when things do go as planned. A famous photographer once said, “The sun does not always shine.”
Why don’t you check back with me before you come out and I'll know more then.