Click on most anyone of those Chicago area courses and you'll most likely find 2-3 within 3 miles. And there's quite a few Blue courses (less than 9 holes) to mix in. Play 9, drive 5 minutes, play 9, drive 8 minutes, play a 5 hole course, drive 15 minutes and play an 18.
At my age now, i'd be aiming at six a day. 8-9-10 in a day is reasonable for anyone in decent shape as long as you're willing to play whichever course you come across. Expect a lot of 1.5 and 2.0 courses that can knock off in 20 minutes or less. Just understand you aren't playing great courses. You're just racking em up. I have to admit, it got a little old after a week of the same thing.