We are in the process of doing exactly this. Lifelong residents of California and I retire in October of this year. We are going full time on the road for a while. Sold our home in Calif. and have just become residents of So. Dakota. No State Income tax, no SSI tax, and no tax on my pension. You have to make one trip there to have your photo taken for your driver's license but that is all. My wife and I flew out last week on Thursday and back home on Friday. While there we got our licenses, registered our vehicle, and registered to vote. All needed to establish a domicile state. Check out www.dakotapost.com for details. They will guide you through the whole process and provide you an actual street address instead of a PO Box. PM me if you need more info.