I commute on a Trek 7200FX that I bought a couple of years ago. I am equipped with a Trek trunk bag with small panniers on the sides. I usually drop off several days worth of clothes on my way home from church on Sundays but if I forget, I just roll them up and put them in my bag.
I live 9 miles from my office so it takes me roughly 42 minutes depending on traffic. I don't try to kill myself with speed, I just try to ride steady. I have a few decent hills and in Missouri we have this wonderful stuff called humidity. I actually like hot weather so the fact that it gets 95-100 in the summer is no big deal, I just drink plenty and take my time.
I ride the roads, not sidewalks. About half of my commute has a bike lane, about 3 miles of narrow blacktop near my home is the only bad part (has lots of impatient rednecks). Once I get in town the portion of the streets without a bike lane are wide enough that motorists can get around easily because it's 4 lanes.
I am an LCI and do firmly believe sidewalks are dangerous although there are some exceptions. I'd like to find a way to reach the many riders in Columbia that ride on the wrong side of the street facing traffic. I've decided that approaching them on the street won't work but if anyone has ideas let me know.