Circumnavigating North America in an Electric Car - where to buy? [closed]

Having recently completed a 50,000km road trip through 30 countries from Australia to the UK, we’re now planning the next stage of the journey, a 6 month circumnavigation of North America, this time in an EV. Starting out from LA in April we plan to drive north as far as we can, to Alaska if possible, then across Canada to Newfoundland and Nova Scotia before heading down the east coast to Georgia and across to New Orleans and the canyons of Arizona and Utah, returning to LA in October. Whilst the initial plan was to ship our existing car from Sydney to LA it would be way better for the planet and way more cool to do it an electric car, although somewhat way more challenging.

As no one is likely to be foolish enough rent us a Tesla, and we are as yet unfamiliar with the practicalities of buying and registering a car in the US, any advice as to logistics would be very much appreciated.

Buying a car in the US For example, is it practical to buy, register and insure a car in the US as a foreigner/non-resident? So far our enquiries suggest its doable - you don't need a US licence to buy or register a car, (a foreign licence/IDP is required to actually drive it) and Progressive Insurance are happy to quote for a foreign licence holder, albeit at a high rate.

However that gives rise to the question of where to buy the car in terms of residence for registration and sales tax. BC was suggested but sales tax/GST/PST is prohibitively expensive at 15-17% so the US seems a better bet. What proof of residence would we need to provide? Can we use a relative's address, or simply rent an apartment for a few days or a mailbox? As we are not actually resident anywhere in the US and will be moving from state to state, are we free to buy the car in whatever state suits, eg Oregon? Which states permit short term residents with non-state licences to register a vehicle?

As an alternative, can my son, who is a resident in the US, buy the car and then authorise me to drive it, even if being a millennial, he doesn't actually have a driving licence himself?

EV Charging: Whilst we have investigated the charging issues of long distance travel in an EV, through Plugshare, Open Charging Map etc, we're planning to venture well beyond the supercharger network, through Yukon, Alaska, Newfoundland etc. Where there aren't public charging stations, how practical is it to use power in RV parks, small workshops or motels and what sort of connectors/adaptors would we need to take to give us maximum charging flexibility?

Ferries: We plan on making use of ferries eg Port Hardy to Prince Rupert in BC, Argentia NL to Sydney NS. Outside of peak holiday times, would we need to book these well in advance or can we take our chances within a day or two?

Any advice greatly appreciated