If traveling by skyway is fun, then traveling by boat has got to be even better, right? I mean, this is Florida. The St Johns River Taxi & Tours offers a variety of River Cruises that explore the Downtown and surrounding neighborhoods. Grab a coffee and jump on the boat at one of their many docks. (Coffee that I hope was brewed at Bold Bean, Vagabond, or Brew.) There are biking tours, too. Check out Jacksonville Moms Blog's Downtown Jacksonville Staycation post or more ideas and information.
Downtown Jacksonville is also a kid-friendly cultural destination. Museums like The Cummer, the Museum of Science and History, and the Project Atrium at the Museum of Contemporary Art all have special exhibits and areas especially for families. There are also dozens of art galleries and weekly/monthly events, like Riverside Arts Market, Art Walk and almost-daily programming in James Weldon Johnson Park. Even the Jacksonville Symphony Orchestra hosts special, kid-centered, concerts. For more info on how to let Downtown Jacksonville culture your kiddos, take a look at JMB's 'Kid-Friendly Activities and Eats: Downtown, San Marco, & Riverside'.