One possible way to call attention to the path of the railroad, particularly in locations visible from public ways, would be to clear the RoW and emphasize its location with low- or no-maintenance materials. When the MBTA restored service to the Old Colony territory in Massachusetts new stations were built where old stations had been destroyed. At one location—
Whitman—the ruined facilities of a branch line to East Bridgewater lay hidden by years of natural growth and neglect. Someone (the town, the T; don't ask me who) uncovered the remains of the enginehouse, turntable and water tower and marked out the features using different colored gravel. The resulting display is quite interesting and seems to require minimal upkeep.

