I had a natural hospital birth just over a month ago.
I would say that one way to help with pushy hospital staff and keep from being offered interventions is to be a low-maintenance patient. Let the nurses/doctors know that you are planning for a natural, unmedicated birth and you would like to deal with the pain in the way that feels best for you at the time. Ask them
politely not to offer you medications unless you ask for them. If you can avoid it, don't complain about the pain while they are in your room...if they hear that you are in pain, their trained reaction is to offer you an anecdote.
If you have a choice of hospitals, ask around and find out if one of them is more natural-friendly than the others. For example, in my city, there are 2 hospitals. When we visited one of them, they told me that if my water broke I would not be allowed out of bed. (Mobility is very important to a natural birth!) I was glad I chose the other hospital since my water broke 6 or 7 hours before my contractions started to come regularly. Fortunately, my hospital staff was awesome--they let me walk all around and eat and drink as I wished.
As far as handling stress, I agree with what everyone else said about having a CD to listen to. I brought music and something for my husband to rub my back with. I spent most of my labor sitting on a birthing ball and my husband rubbed my back through each contraction. The music gave me something to concentrate on.
Good luck, I hope your birth goes exactly how you want it to!