FWIW, registration by foreigners really depends on the state but I'm a Canadian and I've had no problems doing it on multiple occasion (car and boat registered in Florida several years ago, mh registered in SD a about 3 years ago and another mh registered in VT last summer). On the other hand, I do know that other states (e.g. AK) will only allow registration (even temp tags) by US citizens.
Driver's license is different and I think all states are required to have residency proof now but as mentioned, I don't believe it's required for most states.
Insurance is probably going to be the hardest one. I'm sure you'll be able to find one but from my experience, most companies will not sell you any if you don't have a DL from that state. Often, mail forwarding companies that do registrations as well (e.g. companies in SD) will have some contacts that will sell you insurance.
