Act like your boat is a pickup and the river your backroad: Travel and look for tracks or the elk themselves. If you spot elk the boat WILL spook them from a good distance but that's fine. Shore up a little ways away and put a stock on and set up if you feel you're within 150 yards (or whatever...
1) E scout: Put down markers for access points and potential water sources. When I E scout I look for areas that have water, patches of open grazing terrain (elk are grazers! they love grass) and fringe areas where the terrain will transition. Also for access I have been able to find trails that...