You are right. It depends on which rental car company is used. Some are on JFK, and some are on Will Clayton.
IF the rental car is picked up on Will Clayton, then Will Clayton takes you easily to 59 South.
IF the car rental is on JFK, I would go south to Beltway 8 and then head east for a mile to 59 South. That’s just me.
If the time of day is 7-930 a.m. I would consider the Hardy Toll Road into Houston to avoid some of the inbound traffic. Otherwise, 59 South is better.
Ok.. thanks. I think, pretty much ALL rental cars are on JFK now. They ALL moved there a few years ago.