First, let me say that the question of Domicile can be a complicated legal question — especially if you have complicating factors such as owning property or holding a job in a state other than the one you want to declare as your domicile. I am not a lawyer and this is not legal advice. If you need it, get professional assistance.
A couple very good resources for information on domicile are the following:
Escapees: https://www.escapees.com/education/domicile/
Technomadia: http://www.technomadia.com/2012/07/chapter-9-nomadic-logistics-domicile-mail-taxes-banking-and-voting/
• Registration costs for vehicles, including excise taxes
• Convenience of renewal of registration and Driver’s License
—– Vehicle inspections, in person renewal requirements, etc.
• Vehicle Insurance Costs, including Full Timer Liability insurance
—– Dependent on exact zip code of Domicile
• Sales Tax costs for new vehicles
• Health Insurance, availability and cost
—– Availability of plans covering you when out-of-state
• Taxes on Income, Retirement Income, Social Security, and other income
—– Highly dependent on your personal financial circumstances
• Personal Property Taxes (or lack thereof)
• Availability of reliable mail forwarding service
—– At least one of the private mail forwarding services in SD has closed; Escapees will be around for the long term.
• Marriage, family, divorce and common-law rules
• Estate & probate taxes and laws
• Handling of Jury Duty requirements
• Rules for establishing residency – how long you must be there before you can get driver’s license, etc.)
These are certainly not the only considerations, but they do provide a good starting point. They are not necessarily in priority order, and besides your priorities will undoubtedly be different than mine. There are both financial priorities, and personal priorities.
Financially, I would recommend creating a spreadsheet of the various costs associated with each location you are considering. You can get pretty good estimates by going on-line — registration costs, sales taxes, etc. are public information. You can also get estimates from insurance companies for your vehicles, health insurance, etc. based upon the zip code you are considering.
Personal priorities are just that, personal. We eliminated South Dakota from consideration because you must renew your driver’s license IN PERSON in South Dakota every five years. That may not be a problem for you. After you have all of your information, then you can weigh the results and choose the “right” domicile for you!
For other aspects of making your decisions about RV Living, here are other posts on the subject: RV Life & Technical Details