Hi Check out treasurenet.com -gold prospecting section, heaps of info on there. Careful not to go on any claimed areas though - they get really angry about that over there, and it just isn't safe to try it! Ask the same question on that website and you may well get invited to try areas - claims with the owners. There is probably info on that site as to where you can go without problems too, heaps of reading on there and some good videos too.
You shouldn't have any problems travelling USA Canada with a detector as it is not so unusual over there.
Good luck NUGGY