I’m from the Chicago area and a Cat4 also, so I’m a bit partial to Intelli. I’ve done the whole week once and other years have handpicked a few races. If you do choose intelli I’d really suggest that you make sure you get to the Glen Ellyn race. It is an excellent course with many turns around a lake. Its exciting to race and exciting to watch.
There are a few very fast days, they’ve used a race track, a road race on the south side of chicago, the Elmhurst crit, the Elgin Road Race and the final day at Fulton Market (although not technical, this course is more fun than it looks).
Then there are some technical courses, W Dundee, Niles and Lake bluff.
You can have a look at NorCal cyclings YouTube channel for some pretty good course reviews.
As far as ToaD I have much less experience. But I’ve noticed that these might be the hardest, but really fun Cat4 races available. I went to I believe the Bayview crit in my first year of racing and the field started so fast I was off the back and I didn’t know WTF was going on. lol. I learned a lot that day.
I think either way you’re going to have a really great time racing. And since you are not going to be doing the whole week you can probably race a few double days.