When I was doing routes, it was before being able to use the phone to enter reports on the fly. I would do the following:
1- Map out the route
2- Start with as little gas in the tank as possible to make it to the first station on the route
3- Carry 2 each 5 gallon gas cans
4- If the fuel purchase was based on dollars and not gallons, I would use premium if possible
5- Use gift cards for fuel purchase, so you don't run into credit card problems.
6- Have a cheat sheet for the evaluations, some of the MSC have forms themselves, but they are multi page, and a pain when doing many shops in a day.
7- carry a charger/ cables to make sure the camera/ phone battery has enough charge to make it through the day
8- Work smart, and get your system set so it takes a max of 20 minutes on site per location, including taking multiple photos if that's part of the shop. If possible, aim to be at 3 stations per hour
Doing this, depending on the client and route planned, I could complete anywhere from 20-30 stations per day, and wind up with a full tank of gas, full gas cans, a bunch of oil, windshield fluid, bottled water and snacks. I have a friend that has a car repair shop, and he would get the oil/ windshield fluid and any excess gas from the cans. He also kept the cans stored for me since I don't have a garage or shed.
Philadelphia Based, covering Eastern Pennsylvania, Delaware, New Jersey, Maryland