$400 a month sounds low cost for Columbia. If you need lower cost real estate, consider Camden or Sumter (there could still be some lower level trailer parks around Shaw). Real estate values start dropping 30-40 miles outside Columbia, but then you must weigh additional cost of the commute.
Trailer parks that take RVs usually have lower long term rates than RV parks or campgrounds.
Tom Test
Itasca Spirit 29B