Congrats on your new hobby!! I just bought a road bike back in May and am completely hooked.
As far as gear goes, for the first two weeks or so of bike-ownership I rode in tennies, regular shorts, a running top, no gloves, and a helmet. I wanted to be sure I was REALLY positive about the whole biking thing before I bought a bunch of gear. (and now I stalk steepandcheap.com and search the catalog here at TE for cool bike stuff....so addicting...)
The biggest comfort issue I had in those first weeks was with my "sit bones" and girly parts. Once I got my shorts I thought, oooooh, THAT'S what I'm supposed to feel like! If you expect to be on the bike for a good portion of that 9am-4pm, you might want to consider, as others have said, inexpensive shorts with padding. You might want to check out the thread that begins "kinda personal, but..." for information about what to wear underneath them...and for a good laugh, too!
Gloves might be good, too, in case you take a spill, but I've seen several riders out there without them.
Have a GREAT time!! I grew up in the Baltimore area and really miss it. I love Ann Arbor, but sometimes I miss those Maryland flags!!
