Wait a second. Did I read that right? How can tire be both a tubular and clincher? Isn't that an "either/or" kind of thing?

Actually, I have a question for those of you that ride patapsco valley. I've seen at least one ride on bikely that goes from Levering @ rt 1, past the thomas viaduct, and all the way up river rd going past where it appears to end on google maps and all the way to Bonnie Branch road.

Question:

Is this wise to attempt on a road bike or is it some kind of bushwack singletrack experience? I am thinking of trying it this week on my way home, but don't want to get all the way in and then turn around if it is not doable.