We are retirees that have time and no calendar issues, Free as birds. We are thinking of flying to San Diego and then driving back across the southern states. Thinking about a vehicle; rent one, buy a used or whatever. What are the advantages and problems associated with each. Spend $10,000 for a decent old Honda or Toyota van and sell it when we got back east. Getting a title promptly, registration etc could be issues, USAA will insure a purchased vehicle with a phone call. Ideas, pitfalls?
Go for the rental. I checked Enterprise for a three week rental picking up at San Diego International Airport and returning to Miami International Airport. Renting a luxury class vehicle for that time was listed at $3000 with the extra insurances you might choose it might get up to $4500. Compare that to the kind of used car you can buy for that much and it is certainly a win.
With long distance rentals like this always look airport to airport, don’t use the local franchise store fronts.
But, you say you would resell the used car when you get home. Odds are you still won’t break even see the Road Trip for UK Traveler question mentioned in a comment for more about that. However consider how much avoiding all that hassle is worth to you. Dealing with another state’s bureaucracy and that many used car salesmen would put me off it for sure.