I look for an outside island, and look for easy-in ... easy-out. Sometimes you've got to circle the block to come in a different direction. AND sometimes we just have to drive right on by. Diesel is more challenging than gas, because sometimes there's only 1 pump for diesel, and you've got to find it. That's not easy when you're dragging 35 feet behind a truck that takes a cornfield just to turn around in when not towing anything. We avoid fuel stations in towns when towing, simply because of the tight turns, limited access, and sometimes no diesel at all.
I never let my fuel gauge get more than 1/2 empty when I refuel. Even when not towing. For me 1/2 IS empty. When it gets to that point, I am aggressively looking for another fuel station.
Someone on these forums recommend the I-phone app 'GasBuddy.com" and I loaded on my phone. That has truly been a life saver for us. Because it can pin-point your location, we use that app when were in new territory. Although not like a GPS system, it does give a good map of where you're at and tracks you as you travel. So it serves a couple really good purposes. Plus, it's absolutely free and you can select to search for fuel stations based on availability of fuel grade, including diesel, and it give the price per gallon at each station. If you don't have the app, get it. You'll wonder how you lived without it. The maps also help to determine if we can actually get into a fuel station or not.