I rode the Katy trail last October, and am still cleaning the limestone grit out of various parts. I replaced the chain within 1000 miles of completing that ride, more quickly than I would have normally expected (but there were other variables). Latest casualty was the saddle clamp on the seat post--the saddle developed an annoying squeak so I took it apart to clean it and guess what I found. A few weeks ago I had to remove and service the jockey wheels on the rear derailleur.

Day to day on the trail, I wiped down the chain and lube it if it got wet that day, no different than any other ride. There's never a problem finding a suitable rag roadside especially in areas of recreational boating. Nice towels often get left on boats, apparently.