Renting a car in the USA - need insurance help

Hey everyone,

I'm going on holiday to the US next week. We want to rent a car.

We've booked a Nissan Frontier (pickup kinda thing) which we were due to collect from Enterprise RentACar.

We are keen to use a different insurer as Enterpise insurance seems super expensive. BUT the problems are here:

1. does the car rental include 3rd party damage insurance (or any insurance anyway)
2. As we booked a pickup (not a traditional saloon etc.) does this mean we need commerical insurance?

Any advice would be amazing.