If you're not 100% set on the 4th, and you really just want awesome fireworks -- I would recommend checking out the Aquatennial celebration in Minneapolis. It's one of the biggest and most expensive fireworks shows in the country and it happens in the middle/end of July. The 2014 date was July 26th, I don't believe 2015 has been announced but I think the fireworks would be July 25th.
Plenty to do in Minneapolis as well -- catch a Twins game at Target Field, sketch comedy at Brave New Workshop (oldest improv theater in the country, highly recommended), lots of other theater, plenty of parks, Mall of America (including indoor amusement park if you have kids, plus, Legoland), and don't forget a Juicy Lucy.