I'd labor at home and even consider delivering at home if you feel that could be an option for you.
My second birth I was 50 lbs overweight and had my baby naturally. I recommend choosing your delivering position. Hands and knees and squatting can be wonderful positions for delivery. Lots of staying upright is good for helping with dilation. Laying down for most of your labor and delivering on your back like what is typical is a very bad plan. It slows things down and gives a higher chance of tearing.
The prenatal pilates could be really helpful. I'm going to start doing that once I'm done with the nausea part of my pregnancy. I did pilates before getting pregnancy and for the first couple weeks before my nausea kicked in. It just feels great after you've done it for a couple days a week for a couple weeks to a month. You get way stronger and it would likely help with back pain and all that as well.
Read up lots on natural birth methods. The more you know, the more confident you will be. Look up successful natural birth stories too.