Unfortunately I live in Massachusetts. I'm not going to buy two plane tickets for a day hike (or even two). It's entirely possible that I will only visit the Grand Canyon once or twice in my lifetime (there are so many other places to go in the world and even within the US and work gives me limited vacation time), so I'd really want to make a visit there count as much as possible.
If you stick to the Bright Angel trail, I wouldn't worry too much about going alone as that is a well traveled trail. We went down the South Kaibib trail, camped several nights at the bottom (with a dayhike to Ribbon Falls), and back up the Bright Angel with a third night at Indian Gardens (really loved sunset from Plateau Point). We took it easy as we were more beginner backpackers at the time, but still enjoyed ourselves. We did the trip in November around Thanksgiving time.
In general I found the nps site useful in planning a trip. If I recall correctly this website had some good info on trail descriptions:
http://www.bobspixels.com/kaibab.org/
A general southwest site I like for planning (especially the driving distance graph):
http://www.americansouthwest.net/index.shtml
I'm a backpacker and we usually backpack on most of our vacations (well, we did pre-baby anyway
), but I do think day hiking (or at least short one-two night backpacks) are a great way to see the Southwest, so don't rule out day hiking. Keep in mind you will need to carry a lot of water, which can really add up on an extended backpack.
If you feel that you won't get back to the Southwest in a long time, consider seeing more parks (especially since you are interested in photography -- so many great subjects and landscapes). While I think the Grand Canyon is impressive and a wonderful place to visit, there are other parks I like better (especially Zion and Escalante). Even with just a week you could easily see the North Rim, Bryce, and Zion. The bonus of the North Rim and Bryce in the summer is that they are cooler. In Zion you could do the famous Narrows (backpack or dayhike) -- since you would be hiking in a river it would be a nice hike for summer time (provided no thunderstorms!).
You mention at this time you have to go during summer as you are in school. Are you dead set on the Southwest? I love the Southwest and it's one of my favorite places, but for me personally, it wouldn't be very enjoyable in the summer time (I don't do heat very well). You mention there are so many places you'd like to see -- is it possible to go some place else fabulous (like the Canadian Rockies, Sierra Nevada, Tetons ... endless possibilities) and save the Southwest until you are out of school and can go in the spring or fall? I don't mean to be a joykill or discourage you at all, just throwing in my two cents based on my experience.
I don't have any of our Grand Canyon backpacking pictures posted, but there are a few from an unplanned stop there on our last Southwest trip. There are pictures from other parks in these galleries in case you're interested:
http://www.pbase.com/pudgy_groundhog/southwest06