Tri Bike on NCR trail?

I can't comment on the alternate route, but the surface of the NCR is hard packed crushed gravel and not paved. So, you might be able to get away with it, but it would be a rough ride I would think plus too much of a chance of flatting with that surface. Better for fatter tire bikes. I wouldn't try it myself. Perhaps someone else has actually tried it and also could comment on the alternate route.

I took my road bike (Trek Lexa) on the NCR trail a few weeks ago. A bit of a change from the cheap Schwinn I had been riding on it from Target, LOL.  My bike did fine, no flats, no visible alignment issues... as others have said it is not paved, but crushed/packed gravel and parts of it are rough.  I did see plenty of other road bikes on the trail, though no tri bikes.  I spend most of my time on the northern section of the NCR between the M/D line and Monkton.  The section south of Monkton is more compacted and a bit smoother. I've driven Falls road past Prettyboy and if memory serves it is narrow and probably not ideal for cyclists.  It's been a while since I've been up there, but I think after a certain point Falls road is gravel too - that's pretty far north, though.  I'd go NCR trail, personally, but I'm more comfortable riding on the trail since there aren't any cars to contend with except where the trail crosses roads. 

thanks guys I decided not to do the ride.  I think NCR sounds like a good candidate for a CX bike.  I just need to finish building it.