If you are coming up Highway 93 there is a fairly new place just about 5 miles before town called South 93 RV Park. It looks like a nice place driving by but I have never stopped there. Their web page is
http://gocampin.net/south93rvpark/ Their address info is: 2404 Jorden Lane
Twin Falls, Idaho USA
Phone: (208) 326-5092
If you like KOA's there is one north of town also about 5 miles. Their site is
http://www.koa.com/where/id/12109/ Address is: 5431 US Highway 93
Jerome, ID 83338 (208) 324-4169
If you are heading towards Boise after coming through Twin then you may be interested in these places along the "Scenic Highway 30 Route"
Miracle Hot Springs
http://www.mhsprings.com/ 19073 US Hwy 30, Buhl, ID 83316 208-543-6002
This place is about 30 miles Northwest of Twin but is on the way to Boise if you are headed that direction.
If you need more info or would like meet up when you come through give me a call 208-732-5585 or e-mail me -- email address removed --