What I'm working with this year, coming from sea level, is a first rifle season in CO where I'll be spending almost all my time over 10K, and probably some hunting over 12K. I'm going to be in the best shape I can be, try and get there 5-6 days before the season, take it easy acclimating, and hope that helps. Tie that in with drinking a ton of water, potentially supplement with something like Altitude Advantage, and hopefully I'm ready to go by opening day. Want to avoid Diamox if I can, but have to think about it and research some more.
I've been to Wyoming and Montana 5 times, and never cracked 10,000' I was a little winded at times, but never any sort of Altitude sickness.
When I was younger, I did fly into Denver from NYC, drive up to the mountains and hike a 14K footer the next day before heading to a wedding in Vail. I'm in better shape now, but that was only one day at that height.