If you're going out to Colorado, use it to ski the mountain not just the parks. By developing park skier do you mean beginner or intermediate? If you mean beginner, then going out there won't really help. Beginner features are the same no matter where you are. Just because it's Colorado doesn't mean it's gonna be anymore beneficial. But if you're intermidate/ advanced then Breck's park would be a really cool experience for ya.
If I were you I would use the time out there to experience the mountains as a whole. Go to Breck and go to the top of peak 8. It's an experience all in itself. Ride the terrain that your mountain/ hill doesn't have. Things like that will help you get the most out of the trip.
With Vail resorts you can buy multiple day tickets and go to any resort. I'm not sure what the specifics are and I dont feel like looking it up but when I went there I bought a 3 day pass and was able go to vail, breck, keystone, and some other ones. It's a pretty good deal if you chose to do that.