AllTrails
8.7
The most complete trail database in the US, and the reviews are recent enough to tell you whether a trail is muddy, closed, or busy this week.
Free tier is usable; the paid plan runs about $36 per year.

The best US city to visit without a car
Chicago is dense, walkable, and served by more rail than almost any American city, which makes it the rare big trip where renting a car is usually the wrong call.
Two airports, a national Amtrak hub at Union Station, and a downtown you can cross on foot in 30 minutes mean your transportation decision here is mostly about how you arrive, not how you get around.
Train
Union Station is the Midwest rail hub, with corridor service from Milwaukee, St. Louis, and Detroit.
Flights
O'Hare for connections and international routes, Midway for cheaper domestic point-to-point.
Driving
Doable, but expect $45 to $75 per night for downtown parking.
Rental Car
Only worth it if you are day-tripping to the dunes or Wisconsin.

One of the strongest collections in the country, and two hours is enough.

The single best orientation to the city, from the water.

18 miles of car-free shoreline with skyline views the whole way.

Reachable by train, with real dune climbs at the end.

Worth planning a trip around between April and September.

Taquerias and murals in one long, cheap afternoon.

18 car-free miles along Lake Michigan, the best urban ride in the Midwest.

Dunewood Campground puts a national park 90 minutes from the Loop.
Two full days covers the essentials and three lets you add a day trip or an outdoor morning without rushing.
Check the getting-around notes above first: in some cities transit and walking beat a rental car outright, and in others a car is the only practical option.
The tools and providers that fit the way this trip actually works.
8.7
The most complete trail database in the US, and the reviews are recent enough to tell you whether a trail is muddy, closed, or busy this week.
Free tier is usable; the paid plan runs about $36 per year.
Best used as a price check and a way to filter for genuinely refundable rates rather than as your only lodging search.
Varies by market; always compare against the hotel's direct rate.
Strongest for skip-the-line attraction tickets and half-day tours you would otherwise queue for.
Attraction tickets from about $25; half-day tours from about $70.