Profession (sailor) is applicable in many cases but this is not one of them - back strength plays a greater role than experience this time.<br/><br/>For places to investigate, you generally have free reign of where you want to direct your check result within reasonable limits. For NPCs you can easily interact with those assigned to the same jobs, while for others further away you would need to basically use the shirk action (replacing the perception check with the interaction skill check).<br/><br/>For influencing NPCs, non-Diplomacy checks are possible for example if you want to lie to them, just keep the potential consequences in mind.