I am not currently active I was in the Marine Corps for six years.
Yes- you get 30 days leave/year.
Yes- I used it during hunting season
Yes- it was probably the best thing that I ever did and with the training/experience that I got, I was able to get into a great career when I got out.
No- You are not guaranteed to get leave whenever you want, especially in the current environment. If you are assigned to a ship or fleet and they are on deployment guess what your going and you may be gone 6 months or longer, you can take leave before or after deployment.
You can however set yourself up- I don't know what MOS (Job) your looking for but' if you choose something land based, get a guarantee where you will be stationed for X # of years 2-3 (Alaska, Virginia, San Diego) whatever. You will have a greater likelihood of getting leave when you want it.
Don't let the forest get in the way of seeing the trees. I lived in California for 8 years. 6 Military/2 work. I was like a fish out of water, but I made the best of it... They had good good duck hunting, dove hunting, awesome coyote, spear fishing, deep sea fishing etc. etc. Then try to work vacation around the holidays/rut etc. I know its tough to leave what you love, but if you need this experience to further yourself and make a future for your family GO 4 IT!
Also it is very honorable (I.M.H.O) to serve your country in the process!
The time will fly by it seems like forever to you know ,but it will be over before you know it...Who knows you may decide to stay in.
Look into the other branches as well, for instance Scott Air Force base, southeast of St.Louis... 4-5 hour drive to Iowa....Outstanding hunting in the area...Hunt there...come home long weekends, holidays, leave hunt Iowa and Illinois ...etc..
Set yourself up!
GOOD LUCK!