Other Car Rental Programs (ie. Alamo, Enterprise) - Tough NY-FL one-way Apr.6

I'm scheduled to bring RV North from Miami April 9. Problem is at start: finding reasonable one-way Southbound. Cheapest I see is Hertz and Avis, just under $100/day full-size. But I'd prefer 7-passenger deal: any rental company code out there?

Kindly Message me, if there is a good CORPORATE one-way code for any rental co.