One strategy is to split the rental. In cases where you're paying a higher base rate for the duration of the rental due to a remote dropoff, it may pay to rent one week for a straight return, then a separate one day rental for the one-way.

Of course this would only work if you knew exactly when you're going to do the drive over, and you'd have to be able to fit the car exchange into your schedule.

This would also allow you to use coupons on the weekly rental that would otherwise not work on a one-way, since it's now a traditional rental.