The only issue I have with Enterprise is that their current practice is to pass your phone number to a third party that will contact you after your rental for "market research." When I rented a car in Spokane, I screamed and stamped my feet and said, "I don't want the call" and I never got it. When I rented in Grants Pass, I tried to scream and stamp my feet and I was told, "we don't have any control over this." My understanding, under the DO NOT CALL rules, is that if you insist that you are on the DO NOT CALL list, and you insist that you don't want to be called, they are obligated to honor that request. I sent a formal complaint to the Regional Office, and I was told I was put on their internal "Do Not Call" list. However, the manager who did this for me didn't know whether the internal list covered nationwide, or whether it covered just that Region.
GRANTS PASS, OR
There is a good selection of RV Parks in Grants Pass ( http://www.rvparkreviews.com/regions/Oregon/Grants_Pass.html ) where cars can be delivered to you. The two closest RV parks are Jack's Landing and Rogue Valley Overnighters.
There is an Enterprise site in Newport. Here are some RV parks available. I haven't personally stayed at any of these sites, just noting that it's there.
You can stay at either:
Fidalgo Bay RV Resort
Pioneer Trails RV Resort
and have Enterprise deliver a car to you for the duration of your stay.
If you stay at Riverside State Park, there is an Enterprise office at 1426 East Francis Avenue. This office indicated to me that they were the closest to the State Park and can pick you up. I tried this option. I called in advance and THOUGHT I had made a reservation, and was even quoted a final price, but somehow I didn't get a confirmation number. I called on the day of pickup and found out I didn't have a reservation, but no problem, plenty of cars, they will redo the reservation. I showed up and called for them to pick me up. They picked me up, no problem. I got to the office, and STILL no reservation, but no problem, plenty of cars, they will give me a car for the price quoted. Despite the reservation snafu, I got a car, a PT Cruiser. THEN! I show up at the State Park. Park Ranger tells me that the rental car is ok, as it is within the "one RV and one car" allowance. However, the Camp Host told me that since I did not TOW the car in, it was considered an "extra vehicle" and I would have to pay the "extra vehicle" fee. NO WAY! The Park Ranger over-ruled that one! Other than the snafus, everything went fine. I returned the car the night before I left, and left the next morning.