I try and maintain what I have for the winter and not let myself go. I do this by keeping my diet (Paleo), working out 3-4 times a week and lots of skiing. Come spring, I will start hitting the hills and CrossFit pretty hard. Until about 3 weeks before the start of my first hunt. I will then reduce intensity to avoid injury. But, I will still work out 5 days a week.
Being an old dude, i try not to add much weight after season other than to replace what i lost. After that my workout routine stays the same throughout the year and as ghost noted i try to prevent injuries, as old dudes take a long time to heal