a bicycle path...above ground cold water line...doesn't sound all that complicated unless you left out some critical details....I'll make some assumptions...
Assuming bike path is non-motorized vehicles and is narrow and paved (or unpaved, doesn't matter), open cut the path and lay your coated...
Inspection of pipeline without digging...let's see....
Check for leaks (Walk the line or shut-in pressure drop) is the most obvious and cheapest check, but tells you nothing about the intermediate condition and status of the line. Either it leaks or it don't.
Try a close interval survey (CIS)...
DRL and SRL pipe have to do with the length of the pipe "stalks" and not diameter or wall thickness. This is usually important for the transportation of the pipe from the mills to the suppliers or to the jobsites. By definition SRL is single random length - line pipe with 17.5' minimum average...
