First of all, nice amenities an Chicago Harbors don't belong in the same sentence. Its really a shame, with all of the resources that Chicago has to offer, being a boater friendly city is not one of the strong suits.
Why, I don't know. They are one of the largest municipal run harbor systems in the country.
Most marinas have very limited shore facilities.
A Harbor masters office, and a small store of snacks is the most you will find.
Sure they all have showers and laundry facilities but on a very limited basis.
For example, there are over 1000 mooring balls in Monroe harbor yet there is exactly one shower stall in the Men's bathroom; and they are not very clean.
The harbors and everything related to them are very congested as can be expected from a big city. The docks and moorings are crammed as tight as possible to get as many boats in as possible.
Parking can be a real pain in the butt.
They are extremely expense for slip fee's. Full service marinas are not on site and require either going up the Chicago River or the Calumet River for servicing.
That being said, Chicago is a great place to sail out of.
Lots to do and the skyline lite up on a starry night is an unbelievable sight.
Fireworks, outdoor events, Rock Concert, Blues Festival, taste of Chicago all happen within easy access.
We did it for over 25 years and we still return for visits.
As far as access to the loop and downtown, your best bet is Du Sable Harbor. If you like mooring balls, Monroe Harbor has over a thousand; as was already mentioned. The protection at Monroe is not the best and the harbor can become very unruly. Not pleasant for a lot, but we never complained.
In recent years there was a long waiting list to get a slip, but that has changed and I am sure you will get right in, but be ready for a hefty slip fee.
As far as weekend sailing destinations, they are few and far between, not like what you are used to up on Grand traverse. Michigan City is the destination that most cruise to as it is about 30 miles from Downtown. Other than that, there is not a lot; Waukegan and Racine to the North but they are not exactly day sails or weekend trips in my opinion.
As far as what to do in the city, your choices are endless-you are living in a world class city; Shopping, dinning, theater, sports teams, etc. All the best of the best, well maybe not some of tthe sports teams.
Other harbors worth checking out on Chicago are Belmont, Montrose, and Burnham.
I sailed out of Monroe Harbor for over 25 years and loved it, but you have to go with the flow and be ready to tackle some hassles. We moved over to Michigan about 5 years ago and have never looked back, but like i said, still return for visits and I still race the Beer Cans on Wednesday evening. We love the city and all it has to offer, but we also enjoy not having to deal with all that comes with it.
Start here for some info.... Chicago Harbors - Westrec Marinas
If I can be of any other help, let me know. I do have some experience.