We're loving the Greenbelt here in Boise. We can access it just a block from our apartment, and ride our bikes on it all the time. Eli asks to go daily so he can do the dirt bike track. We also love the little lakes along the way, water can keep the kids busy (and happy) for hours! There's a playground we can ride to just about a 1/2 mile down the track, and best of all the weather has been very permitting!
Eli keeps asking if we know any other 5 year olds that like to do jumps, umm we'll keep looking.