The petro truck stop in Reddick, FL (listed as ocala), does carry Delvac 1. Not in the store though, back in the truck lube shop, which is about 100 yard behind the main truck stop restaurant/store. They are expensive there though, it was like $24/gal. Most all of the time I just order online at
www.avlube.com and it's shipped to my door in 2 or 3 days. They charge $81 per case.
Tiffin, FYI, the E300 holds 7.5 quarts, and I've found that by adding 7.3 quarts after draining, I get to the perfect mark on the dipstick every time. Just can't get every bit out, and you DON'T want to overfill. The dealer almost always overfills e300's because they're so used to doing all the other e-class, which hold 8 quarts. Don't forget to ask the mb shop for a new drain plug washer
I tried a K&N filter on my E300, and within 2 weeks my MAF sensor failed. Others on the TDICLUB forum have noted that the oil from these filters has caused their MAF's to fail as well. This is a hotly debated topic however. Most tend to say that the amsoil tack oil won't 'blow' into the maf and ruin it, as it's stickier/tackier than the k&n.
There was a controlled experiment done with a stock paper filter, amsoil dual stage foam filter and a K&N. The amsoil was the best at filtering by a good margin, and had similar airflow to stock. The stock filter was the poorest at filtration and airflow. The K&N had the most airflow and middle of the road filtration. They've been called K&N dirtsuckers too many times, and ruined my maf for sure. I'd avoid them. I did however just purchase a dual stage amsoil foam filter for my tdi. It looks really oily, as they are preoiled from the factory. I plan on setting it in the sun to dry for a while before I install it, and waiting for my current paper filter to be used up, it has about 8k left in it.(20k air filter changes).
Tiffin and others interested in making the switch to a premium diesel synthetic, I'd highly recommend running one or two changes of the delvac1 and dumping them in a short time, maybe 3000 miles. The additives package will really get depleted as it cleans out the crap from the past inferior oils, so its good to do one or to short changes to flush. Engine flushes are reputed be harsh on seals etc, and I think should be avoided, although I have no particular experience with them.
I know this is long, but here's a link to some delvac info.
http://dallnd6.dal.mobil.com/Apps/DS/_39gj50ko_/MobilPDS.nsf/26b7c4b33367a4a086256665004e4266/60d8a76e857b7e71852567b60072913a?OpenDocument
Here's another.
http://www.mobil.com/USA-English/Lubes/Product_Information/Diesel_Engine_Oil_Collection.asp
Enjoy! Also i can't stress enough testing your local fuel source for quality/contaminants. Avlube offers diesel fuel test kits. I dont work for them and am not affiliated in any way, but those test kits are the only way you can truly know what you're pumping, and if your expensive injection system is getting worn out by high particulate fuel or not...