Well, I finally changed the oil again. I looked back and realized that I was overdue for a oil change. This one was at 275,600 miles. Added about two quarts in between changes, so not much leaking or consumption by the engine in that time.
Total cost was right at $30. $9 and something per gallon of oil (2 gallons total) of Mobil 1300 Delvac 15W-40, and $9.29 for the filter at AutoZone.
I would have saved a little on the filter price if I had payed attention and ordered one earlier, but I wanted to get it changed this week since I was already overdue for an oil change.
This past weekend I also changed out the primary (plastic) fuel filter. I noticed that it was a little sluggish on takeoff, and didn't smoke no matter how far I pressed the accelerator. I checked the fuel filter and it was nearly black inside. Changed it out for a new one and its running much better. I'll post some pictures of the before and after of the fuel filter to show how bad it really was.