Hmm, I didn't know that, thank you, that changes things. The fact that the dropoff fees make the car rental substantially more expensive combined with the hassle regarding the 6-month VISA, I decided to stick to a 90-day trip for now, doing one big loop.
Unless you use a specialty rental service that will enable you to rent the same vehicle for six months, just about every national car rental service has a maximum term of 30 days per rental. And those drop fees will really add up!
And I moved your thread here, since as a policy we tend to move all trips that are intended to be longer than 30 days to this section of the Forum.