Yellow pine, white pine, fir, spruce, red or yellow cedar, mahogony and probably quite a few others will work just fine, though the weight of the boat will vary dramatically depending on your choice. Adjust the size of the gunwales to suit the strength and stiffness of the wood you choose. For gunwales, stringers, deck beams, and bow/stern plates, kiln dried wood works just fine. You want green or air dried wood for the parts that will be steam bent (ribs and coaming), preferably oak or ash. If you have the machinery necessary to turn chunks of a log into usable lumber (jointer, planer, table saw, band saw), you can get green wood from a firewood dealer for a pittance. Otherwise, check with local sawmills, if you have any. If you can't find green or air dried wood, kiln dried should work if you choose the grain carefully (no runout) and soak it well before bending.