I live in the bay area which is the home of the Giants and A's in regards to baseball. Oakland isn't the safest city in the world and I have never even seen a fight at that stadium (inside or out). I usually sit in the area on the map from between 143-135, I really like that area as its close to the field and has a good view and angle of it as well.
Anyways I recommend beer from the tap...garlic fries, hotdogs, pizza, and nachos.
If you can give us the date you are planning on watching the game maybe we can find a good deal for some nice seats. Otherwise I use craigslist mostly as I can have the tickets mailed, emailed, or just pick em up.