Most, if not all, insurance companies require that any household members of driving age be listed on your policy. In most states, however, you have the option to exclude household members so they don't impact your rate and are not insured under your policy.
What you would need to do is have a policy written in your name, add the person who drives you around, and have yourself excluded from the policy. So the policy would basically be yours but you aren't covered as a driver so you shouldn't impact the rate as a driver.
Technically, you only have to insure the vehicle if it is being driven, but the state could suspend your vehicle's registration for not maintaining insurance so you'll likely have to turn in your tags. You should contact your state's vehicle registration office for more information on the tags.
Luckily, that new vehicle you're referring to will be looked at completely differently by your insurance company. With vehicles that have been modified outside of the factory, especially those for disability purposes, insurance companies will cover the vehicle up to the Actual Cash Value (ACV) and the custom equipment would be covered separately.