DannyDuberstein said:
Kid will like the Peak 8 fun park. The alpine slides are a blast. Get there when it opens and the wait to ride the slides is short. Ride them until you are sick of them, then go do the other stuff in the park once the crowd builds and the line for the slides gets longer.
Or go during the middle of the week and it doesn't matter. If you aren't staying at Peak 7 or Peak 8, park in town and ride the gondolas. They're free and run 9am until 6pm. If you park at the Gondolas, the parking cost is credited towards Peak 8 passes. Be very careful on the slide (not the coaster). It isn't built the same as the similar slides the resort has at other locations (Park City, etc). The amount of people that fell off and got fiberglass burns was astronomical.
Get your passes online or at the Gondola station and bypass the really long line to get in. We walked (just at the north end of the resort) back to the Peak 8 (Grand Colorado) and ate lunch at Robbie's Tavern instead of messing with the mess that was eating at the ski resort. I would recommend it.
We literally just got back today from a week in Breckenridge. We rented a house in the mountains just south of town in Blue River.
I'd caution taking the family fly fishing if they aren't proficient fly fishers. Breckenridge is peak fly snob. I talked with both shops in town multiple times as my dad wanted to go fishing for Father's day. In the end we went on Dillon Reservoir and had a blast catching rainbows, browns, and the local landlocked salmon. Caught enough for the entire extended family to eat for dinner.
By the way, watch the weather. It would get much warmer in the afternoons than expected because you're much closer than the sun. Nice and cool at night though.
If you have any specific questions just ask.