Hello E,
Sorry about your recent AN diagnosis, but it sounds like you are remaining very calm as you go though your due diligence. Calm is good. Your determination to continue exercising regularly will also serve you well. Very well, in fact.
My only suggestion is that you consider all THREE treatment options. In other words, in addition to surgery and radiation, Watch and Wait may be a completely viable option, especially for a smaller tumor. Any doctor who does not make that crystal clear to you should be fired (just my two cents). After my 1.4 cm tumor was diagnosed, I was in W&W for almost 3 years before deciding on GK when my tumor grew to 1.8 cm. Check out the W&W brigade posts and you'll learn that others have been in W&W for much longer.
My humble suggestion is that you give yourself some time to adjust emotionally to your diagnosis before making any decisions. Surgery and radiation are both serious procedures and both can result in serious side effects. There may be no need to rush into treatment for a tumor your size. You've probably lived with your AN for years without even knowing it is there. Now that you know it's there, you can probably continue living the same life you've known, possibly with a few minor adjustments.
I wish you all the best,
Petrone