I'm going to reiterate a couple points from the guy you responded too and then make a couple of my own.
Do a walk-through with your landlord before you move your stuff in. Have a sheet and not[e] anything not clean or that has a defect.
This is very important. It can be awkward but do it anyway. I've always been diligent about it so nothing bad happened to me but I've had friends have to pay for new carpet, new paint, etc because their landlord said that all the prior damage wasn't there at the start of the lease term. I would actually note if the place is dirty (floors, countertops, walls, refrigerator, etc) because some places will charge you a cleaning fee even if they don't clean the place. Also, I'm pretty sure charging a cleaning fee is illegal in most states but do your research ahead of time on that because cleaning fees can be $200+.
Most likely you will be signing a standard one year lease, so just because you won't be living there doesn't mean it is not your responsibility to pay your portion of the rent.
This is what I was thinking reading your post. You'll still need to pay half of rent because of 12-month leases. Utilities, excluding trash and any utilities bundled in rent, are his responsibility while you're away for summer though.
I'll also reiterate what s/he said about having a sit-down to work everything out - cleaning, guests, food, etc. Since you've not had an apartment with someone, your expectations may also change during your time there. The important thing is to be proactive about what you'd like from your roommate instead of reactive. If you say overnight guests are fine on weekends but it bothers you more than you expected, talk to him sooner rather than later.
OK now my points:
Make a budget, now. Pretty soon you'll have decided on an apt so you'll know your monthly expenses. Stick to your budget.
(This is in the wiki) Create an emergency savings of 3 months worth of expenses. I'd say don't spend a dime on anything else until you've got this but you're in college and you should have fun. Set a deadline for yourself by which time your emergency savings will be completed and figure that into your budget (if you need $2100 and your deadline is by 2016, you need to put $262.50 in savings monthly starting in May). Once you have the 3 months worth, you can decide if you think that's enough.
I'd go ahead and get a job lined up or start a job where your college is. Finding a job can take time and you don't want to be without one for the first month or two. On low income, college budgets, no income for 1-2 months is devastating.
Good luck!