We began researching this topic over a year ago. We found most counties in OK allow this. We searched for property anywhere in southern OK to be near two of our grandkids. We ended up buying some very cheap land in eastern OK. We installed water, electric and septic. We had two full hookup spots built outside and two inside. We built a 67×50 pole barn because we have two RVs, one small and one large. We plan to build a 16×50 living quarters on one side of the barn at some point. The county has no permits nor do they care what we do. The only permit required was the state permit for the septic system. We did all of this VERY cheap!
Also, we compared OK and TX for which would be cheaper for taxes, insurance, car tags etc. Since my husband is 100% disabled veteran, OK ended up being much better financially for us and since I was born and raised there and family still lives there, it worked out perfectly.