Ike covers the high points well. Like him, I've decided that the best way to avoid moisture (and thus biology) related problems in fuel is to store it in airtight containers. This is a little trickier than it seems because of thermal expansion and contraction of the fuel and particularly the head space above the fuel.
It's not impossible though. The low-tech and simple way out is to bury a (plastic) tank in the ground and let the earth do your temperature regulation. This has the added advantage of keeping the fuel above freezing (and thus gel point) in really nasty weather. As long as you keep the tank full, do the normal moisture control things, and burn through the supply annually or so, you're probably going to be fine.
Water in a fuel tank always ends up at the bottom. If you arrange the tank a little off-plumb it will have a low side. Make sure that one of your two dip tubes goes all the way down to the bottom of the low side of the tank. Hook the generator up to the other (higher) dip tube. You now have the ability to do an aviation-style sump drain of the tank to get all the water out through the low-side dip tube.
No water means no biology. Oxidation is still a concern, however. And once the fuel begins to oxidize it gets more interesting to microbes. The way you avoid this is to minimize head space in the tank above the fuel. Have a look at how wine or beer is commonly fermented. The idea there is to minimize the head space to minimize the surface area of the fluid possibly exposed to oxygen. An airlock on top works well, as might some sort of clear remote header tank with a high dip tube and a sump drain. Modifying a truck overflow tank would probably work well, and it being translucent you could easily see when more fuel was needed.
You can add some EDTA (Sta-Bil) to retard oxidation of the fuel. It does work, and there is no difference that I know of between the common, cheap 'gasoline' and the rarer 'diesel' fuel stabilizer unless the ingredient list says so. I use it in my fuel mostly to deal with the day tank being kept full and the fuel's attendant exposure to moisture.
No matter what you do, there's going to be a certain amount of inspection and top up involved.
Corrosion is mostly dealt with by managing water and biology. There can be acidic fuel or acidic decomposition products in the fuel, but if you're keeping the fuel away from water and oxygen it shouldn't turn acidic and start eating your generator's fuel system.
Lubrication of older injection pumps with ULSD is a real concern. The studies I've seen showed that simplest, cheapest, and most-effective way to deal with this was to add some B-100 biodiesel to the distillate diesel fuel. I think the stated ratio was something like 1:20. Two stroke oil and appropriately filtered WMO would also seem to be appropriate additives, but will likely be more expensive or time consuming. WMO probably will need to be added in higher ratios as well.
