All the above suggestions I have heard of and it sounds like great options. If you're dead set on meds, I have heard nitrous oxide (low dose laughing gas) is wonderful. Works fast (within 30 seconds), has no adverse effects on you or the baby and leaves your system within 2-5 minutes which means you won't be loopy when the baby arrives. It let's your body continue to feel and do what it needs but you don't care about it. It also allows you to breath in as much as you need and only when you need it instead of having a set value.
Try hypno birthing techniques for pain management. You can download from iTunes or go to classes. I know a number of friends who successfully and painlessly delivered using this method. It is what I am planning as I don't want any drugs or interventions. Hot water bath or sitting on a stool in the shower with hot running on your lower back is supposed to be good. Keep moving and keep upright as much as possible. Also try squeezing stress balls with each contraction as it moves the focus away from the contraction.
I really want to avoid anything going into my spine
If you have back labor, there's a procedure where they can inject sterile water into your spine which confuses the nerves and gives a few hours of drug free pain relief.
There are pain meds that get put into your iv but I heard it barely works and makes you sick but then again no one is the same. Talk with your dr and let him know of your birth plan so they know when it's a right time to give it to you
Being in the tub is supposed to help a lot.
Seeing the pain as a means to an end, a good thing, rather than something to avoid.