What he means is to pick a route through the station suited for the larger vehicle. Should not really be a problem for a small class c, but worth considering before entering the station. The end pumps often make entering and departing easier.
Ernie got it right about what I meant.
I'll add this.
Not knowing how much RV driving you have done AND assuming this will be the first time driving the unit YOU will be renting, there are a few things that MAY be different here in the USA.
In big cities, Gas Stations can become very crowded. With the type of RV your renting there is a fair amount of overhang behind the rear wheels. It's easy to hit something with the overhang. Even experienced drivers do sometimes and usually it comes down to not having
planned the exit well enough. Some pumps are designed so you can drive through them and those tend to be the easiest ones to use.
Others you drive in and then have to make a turn to exit - that's where a problem can come into play. Depending on the station layout you might pull in and then someone pulls in behind you - so you can't back up.
What I have been doing in preparation for a trip I'm taking - is use Google Earth and find stations along my route, then I use the street view
to see if they are able to accept my size vehicle with a trailer. Most of the time I'm looking for Truck Lanes because I use Diesel fuel.
I think you be just fine - just drive very slowly when gas pumps, other cars, people, and the dreaded pump guarding is around.
When in doubt stop and get out and look. If you do that you should have no problems.
Hope you enjoy the USA. And I assume you know this but don't forget we drive on the right side of the road.