I just sold my motorhome and it was designed to run on low sulfur diesel only to meet EPA standards. It also had a catalytic converter on the rear of the exhaust so that it burned clean. You could stand at the back of the exhaust and it did not even smell like diesel exhaust at all. I never any problems with mine in 8 years. Over the last couple of years, the new diesel vehicles have a small tank where you have to add a fluid called Diesel Exhaust Fluid (DEF) to meet even stricter EPA standards. Just thought I would mention that.

As far as longer term storage, I used PRI-G additive for mine. They make it for gas and diesel fuels. Diesel fuel without any additive like PRI-G supposed to last about a year, then it can gum up. I have stored fuels using PRI-G and used it two years later.