First time backpacking in Yosemite - please help

[Alchemist]

Hi, I'm going to Yosemite in early August. It’s a short trip but my first time backpacking there, so I hope to sort some things out before leaving. I’d really appreciate it if any experienced backpackers could answer my questions.

My entry trailhead is Happy Isles to Illilouette and exit trailhead is Glacier Point to Illilouette. Here’s my plan:
Day 1: Arrive in Yosemite and spend the night at the backpackers campground
Day 2: Enter the Happy Isles to Illilouette trail and camp at Illilouette Basin
Day 3: Leave for the Glacier Point (via Panorama Trail), take Four Mile Trail and then the shuttles to Yosemite Valley. Overnight at the backpackers campground.

Here are my questions:
1. Are there any major problems in my itinerary? I know my route is opposite to the popular one (most people go from Glacier Point to Illilouette or Little Yosemite Valley), but I cannot get the permit for Glacier Point to Illilouette as the entry trailhead.
2. Water source: will there still be water in Illilouette Creek in early August or should I bring water for cooking?
3. Bear canister: Are the ones rented at the permit station in different sizes?
4. Topographic map: Does the wilderness center or permit station at the Valley sell topographic maps?

Thank you!

[balzaccom]

1. Are there any major problems in my itinerary? I know my route is opposite to the popular one (most people go from Glacier Point to Illilouette or Little Yosemite Valley), but I cannot get the permit for Glacier Point to Illilouette as the entry trailhead.

Yep--your itinerary seems perfectly reasonable. You'll probably end up camping somewhere up along Illilouette Creek, and then hiking back down towards Glacier Point the next day.

2. Water source: will there still be water in Illilouette Creek in early August or should I bring water for cooking?

That's a long way to tote water. There should be some water in the creek.

3. Bear canister: Are the ones rented at the permit station in different sizes?

Nope--they usually just rent the old Garcia cans. plenty of room for everything you need for an overnight trip. If it seems too large, remember that you can put other stuff in there as well,...

4. Topographic map: Does the wilderness center or permit station at the Valley sell topographic maps?

Yep--and also Nat Geo and Tom Harrison maps, as I recall. Plenty of maps to choose from. Although unless you are planning to go way off trail, you won't need many maps on this hike---these trails are very popular and very well marked.

[weendoggy]

My only suggestion is getting an early start when leaving Illilouette for GP. That east facing slope can be brutal unless you do it early to miss direct sun. It can warm up fast.

[Alchemist]

Thank you both, for answering my questions and offering suggestions.