Depends on the tour. Most of my trips are one night with a lot of riding, and I'll use sidi dominators which are basically a road shoe drilled for SPD with some tread. They are not the cheapest, but I think they are the best shoe for this purpose; especially paired with shimano a-600 pedals. If I'm going to be doing a fair amount of walking I'll use a pair of Pearl Izumi X-Alp Seek WRX (which I don't think they make any more, but PI has a lot of spd shoes). If the riding is going to be more casual I may go with platforms and regular shoes or sandals. I wouldn't use road shoes and pedals for anything but racing.