Welcome Tim...I can pretty much ditto everything already said! I've had Crohn's for 20 years, started with a temporary ileo which was reversed...missed it and had another temp ileo that lasted for 8-9 years and now I have a permanent ileo and feel the best I have since before my diagnosis!
I made all my decisions in regards to my ileostomy surgeries and have no regrets...that is really important for coming to terms with your situation.
As far as preparing for your surgery, make sure you are as healthy as possible...I know that doesn't sound easy considering why you are having surgery...but the stronger you are physically (and mentally) will go a long way for your recovery.
My daughter was very young when I had my worst flares and remembers mommy as always being sick...this surgery has given me and my daughter (and my husband, too!) and life of WONDERFUL MEMORIES. I have the strength to do anything I want and no need to find a bathroom every 10 seconds!
Please keep us posted on how things progress...you'll be in my thoughts