I've done it on road bikes-- a normal road race / training tire or slick is very sketchy on hardpack.
If you buy a touring tire with some actual tread it helps a lot, but you give up some road traction and rolling resistance. Something like a Vittoria Randonneur, for example.
I like the Giant Roam 1. If you find yourself wanting a little more road performance, first try some 28-32mm cyclocross tires. (Check with LBS and/or Giant to confirm smallest your rim can mount, but it should be at least 32mm.) You can also mount a true road tire, but I just explained above that it won't be very good on gravel.
