Three Oh, I think you said the key thing when selecting fuel sources - buy from a place with high sales volume. This is key to avoiding fuel with water, algae and other contaminants.
All pump fuel sold in the US is supposed to meet ASTM D975, either #1 (winter) or #2 grades. And the transition to ULSD is not fully phased in, so make sure the pump has the sticker for 15ppm fuel (you still occasionally find pumps still marked as 500 ppm...).
Cetane # is a key index (analogous to octane for gasoline) and it varies widely (and is not required to be marked on the pump). EPA cert fuel allows a range of 44-48 cetane, but you can find <40 cetane fuel in parts of the country as well as cetanes approaching 52 (higher is better). BP Amoco used to sell a "premium diesel" which was 50+, but since the switch to ULSD I haven't seen it around here anyway.
I would avoid biodiesels altogether with this engine mainly because of the size of the fuel filter. Supposedly its approved for B5 but personally I wouldn't risk it with mine. However, some locations don't require the pump to be marked so you may be getting it anyway (not by choice).