I have an oil filter kit and my oil looks brand new when I change it in the fall
Keep in mind the oil pressure adjustment on that thing can be tricky. I found Shell Rotella 15W-40 plays very nice with that setup and usually my oil pressure gauge is welded onto 40 PSI except for a cold start. What I would do different if I were putting in another one would be instead of "2-blocking" the oil pressure adjustment at the aft end of the engine, assuming it still worked well I would turn it up to about 60 PSI and set the filter for 40 PSI. Being at the far end of the engine, the filter valve has a hard time with really cold oil on initial start.
Re the 200 miles:Long range unrefueled motoring trips are not the strong point of A4 powered boat for the most part. I could only get 200 miles with 30 gallons of gas in flat calm weather - maybe. Smaller boats may do much better, put pushing a 35 foot boat upwind is a marginal endeavor for the little beasts. Against any significant weather I would be lucky to make 140-150 miles on 30 gallons. We never refueled in rough weather offshore, if there was wind we were sailing. One passage we did 170 miles noon-to-noon the first day and 180 the second under triple reefed main and storm jib. We passed a big steel ketch under bare poles motoring on autopilot. They were rolling so bad we speculated they might capsize either direction
The modern motor sailing concept of hundreds of miles under power was not a thing when most of our boats were built.
A week long ocean passage under sail for us used maybe 5 gallons of gas for battery charging.