Mate, reading your questions you really have a lot of information to gather before you even think about Salmon fishing.
You state you think the place you want to fish has running water

you will be hard pushed to find salmon in any other type of water except special fisheries.
You may find that for by a rod licence you also have to have a permit to fish the river of your choice + a possible extra permit if you are fishing a tidal stretch
Salmon season starts tommorow and closes on the last day of October, I think there is still a conservation scheme active at the moment where all salmon have to be released until sometime in june/July, you will have to check this out to confirm the situation.
At this time of year there are fish that have spawned returning to the sea
( kelts ) these
must be returned, failure to do so will result in a heavy fine and possible forfeiture of your gear.
All in all mate, I would try and get in touch with a regular fisherman and ask for some information before you start spending your cash, I'm sure there are loads of people out there who are willing to help.
If you get yourself sorted, salmon fishing is magic and you will have some wonderful times to look forward to, just take your time ,suss out your requirements and you will be ok.
Best of Luck
seddo