Hi there hhanse. I know exactly how you feel as I am also in Illinois and bought a home last year that has several large gardens overtaken by bindweed.

Preen will work against the seeds of the bindweed but not the established plant, which is perennial here. As you have probably gathered by your reading that this weed is nearly impossible to get rid of. There are some ideas in the bindweed thread here that I am linking to.

I had a large corner garden (about 700 sq feet) that I pulled out a few precious plants from. These plants had all the dirt removed from their roots/rhizomes so I could remove any trace of the bindweed root system. I weed whacked the rest and have put several layers of black plastic over it. From what I've read, the bindweed will have to be deprived of light for several years (man, this stuff is tough!) before it will die.

In other parts of my garden which are closer and easier for me to scout daily, I am snipping off the bindweed vines at ground level. No idea if this will be effective but I have heard it will eventually exahust the weed of its energy stores and kill it.

I think some chemicals have had moderate success, but I haven't resorted to that yet.

Good luck and please post on your progress!

Here is a link that might be useful: Bindweed thread

Bindweed is perennial, preen won't help, unfortunately. I hate the stuff.

I went out a few days ago and sprayed what I could see with some sort of weed killer. Last night it looked all wilted so maybe that will kill some of it. It is very hard for me to work outside cause about 8 years ago I suddenly developed an allergy to green things. I've broken out in a rash from tree leaves that brushed against my face while on the riding mower. I knew I'd be breaking out in a rash from the poison ivy that was out front and I was right.