I just picked one of these up used from Craiglist that someone had converted to a SS. I love it! I don't know if it was originally designed as a 'cross bike as I don't think they had "cyclocross" bikes back when this thing was built (it even had a 38 tooth biopace ring that I promptly swapped out for a 48 tooth std ring). But as far as the frame goes, it looks like it would be more than capable for 'cross riding, and I've taken it on a couple of dirt paths near railroad tracks and it handles very nicely. Don't know how much off-roading I'll do with it as I've set it up as my primary commuter at 48-16, which is great for my commute but might be a little too hard for any real trail hills). I too was looking for info on the bike, but the only Boardwalks I'm finding are made of aluminium, not this nice lugged tange cromo frame.
I always wanted a Biachni and this seafoam green boardwalk suits me just fine.