You can use Skyscanner to check flights between cities. You can take a flight with a connection in Chicago, or flights with a second connection in Toronto.
BTW, there is no point posting two questions right away on the same forum. I know, I know, you remembered something more you wanted to say. :-) What generally happens is you post your question, get some replies and then add more info if you want to by replying to your own thread.
Another forum you might like to post on is the Toronto Forum. There are regular posters there who are very familiar with points south into the States and might have some good tips for you. Especially if driving is a possibility. Many regulars have driven right down the eastern seaboard to FL. Don't know for sure, but a definite maybe. Here is the link to the Toronto Forum:
Of course you can. A simple search will reveal many flight options--it will involve a connecting flight, or you could drive to Chicago and fly non-stop from there.
However, consider that by the time you drive to the local airport in Madison, wait around for your first flight, connect in Chicago, land in London and pick-up your rental car, you will have probably spent about 6 hours in transit. You could probably drive all the way in 8 hours and save yourself the cost of the flight and rental car.
lolol. What did I tell you? They come to you to answer your question.