Not asking much are you!
1/ No advice
2/ Maples are cheaper on the NA continent.
3/ Like sugar. Anonymous by the pound but they will want to know who you are if you buy a boatload. [note; I'm not American]
4/ Both. Eagles, Maples, Krugerrands, Aussie nuggets etc are a fraud though if you pay more than 5% premium because they are not collectors items. Real collector's items are greatly effected by condition and rareity. You can bulk-buy British gold soverigns which were once circulated at a small premium.
5/ Yes
6/ Try your home town first. Then MAYBE eBay.
7/ No idea, I'm not a US cit.
And I'm not about to give trading advice so will not comment on the likelyhood of $300 gold. The only advice I may give is that worldwide, bullion coins are getting harder to find.
Caio.