I usually travel to and from Kalamazoo west using Red Arrow Hwy/ Staduim Dr. Its a historic scenic route. Lots of interesting things to see.
Kalamazoo has major traffic problems for a "small/medium sized city". Westnedge / 131, Main St. Drake, etc.
Highly reccommend Red Arrow Hwy. I know most people prefer the I-94 nightmare to enter and leave, but I have always found that Rd Arrow is a good route, and a little less stressful pace. If you have the time, try red Arrow/Stadium Dr. Its very pleasant till you get to Ostemo on approach from the west. Stadium moves pretty good even at rush hours, and wil give you plenty of opportunity to get onto any of the major North/South routes. If you get bored can always go a mile or so south and get on I-94 anywhere between Kalamazoo and New Buffalo.
Kalamazoo has a nice old train station, with regular service to Chicago and Detroit. The new local bus hub is open next to it, and busses will take you to all parts of the city from there. The airport is at the edge of town and city busses go there. There are several taxi companies around and all are okay, and charge fairly. You have several choices of car rentals at the airport, too. Most people come here by car, though, and few tourists use the public transit facilities.