Question regarding dog parks and safety and puppy day care especially in Chicago area?

Ok I have a couple of questions. Sorry this is a bit lengthy but I would appreciate any answers

First of all, I do not have a dog yet but am looking into getting one in a year or so when I move to Chicago. I have done some research and seen that Chicago is a very pet friendly city, not only do most restaurants and cafes allow you to have your dog at outside tables but they are also allowed on public transit. Another thing is they have a lot of dog parks and dog beaches, but after some research it appears that the safety of dog parks is pretty up in the air. However, my understanding of Chicago dog's park is that you have to have an ID(or permit) to enter the dog park and to get these things you must present your proof of the dog being up to date with shots to obtain this permit at an office, is this the case? and how do they verify the people at the park have a permit?

Also, a general question about dog parks. I plan on getting a small dog and I am concerned that a big dog may injure it (I'm thinking about getting a hairless Chinese Crested) do dog parks have separate areas for small and large dogs? or special times for just small dogs etc? In the area where I live we do not have a dog park so I have no idea how this whole thing works....

Lastly, does anyone have a website to a place that does doggy day care in the Chicago area or can tell me how much this service cost. I won't be gone for long but I would rather have my dog in a day care program (at least I believe) then having to lock it up in a crate. Also, what is your experience with taking your dog to a doggy daycare is it any good?

Sorry it's long but thanks for taking the time to read and reply!