Hi! We've lived in Greenville for the past 13 years (prior to last January, when we moved to New Zealand LOL). I highly recomend the Natural Mama's group! Erin is the leader and she's a FANTASTIC resource and the group is full of diverse, wonderful women. There are 2 or 3 homeschool groups in town - there is a really large Christian group and another fairly large secular one. I can only speak for the Christian one, but they have field trips and a good number of activities and co-op classes for each age group.
There are a number of really good parks around town and fun activites downtown for kids throughout the year. There is also a LLL group in town, a Holistic Moms group, and I was a part of a doula group, so if you are eventually needing birth services, there are lots of good doulas around to help you out with birth options.
As for vax-friendly docs...we went to Eastern Pediatrics. The male doctor there was "ok" with us not vaxing, though he did bring it up every visit. The female doctors there seem to be much more easy going about not vaxing. I know there are other drs in town that non-vaxing families use. If you contact the Natural Mamas group and get on their yahoo list, they can give you lots of references and just generally help you plug in with "your people" :)
If you want to PM me any specific questions, I'm happy to help! Especially if your DH is going to work at or near the hospital, as that is my hubby's prior employer. :)