What is performed doing this visit.My clock is telling me it's ready even though I've been changing it every 5k. Curious to know what they do and if it's worth the 300 mi round trip.4 1/2 hrs for just an oil change seems like a waste of time

 

I assume you mean the odometer countdown service, and not the annual oil change. If so, it should include a brake fluid flush, check the brakes, top off all fluids, and some new filters. Not sure if there is anything else.

It may be required for warranty maintenance. Check with your dealer about that if you decide to skip it.