Welcome to Coin Community. The answers to your questions are easy, the right thing to do...not so much.
First, the amount of money you're going to realize from selling these coins is directly proportional to the amount of time and work you want to put into selling them. Selling them to a dealer is quick, easy and convenient, and guarantees you won't get much more than half of what they're worth if you maximize their exposure in the proper venue.
Second, the value of these gold pieces varies greatly by grade. None of the three are particularly rare; if heavily circulated, you'll only realize a hundred or two apiece. If they're Uncirculated (Mint State), values could range into the thousands of dollars each, depending on the grade. Coins are graded on the Sheldon Scale of 1-70, ranging from Poor 01 (are you sure it's a coin?) to MS70 (flawless under significant magnification). Mint State coins start at MS-60. With any of these three coins, once you get past MS-62 or so, you're getting into serious money territory. Using the 1914 as an example - in MS-62, value (in the real world, not some published price list) is something around $1200 (in a reputable
TPG's slab). One grade up, MS-63, and you're looking at $8000-9000 for the same coin.
Like I say, value varies greatly by grade.
So, one of the things you're going to need to get your best price for these coins is to have them graded. This is optional, but most prospective buyers would want to see them encapsulated by one of the three major Third-Party Grading Services - PCGS, NGC or ANACS. More on this later.
Third, you're obviously going to get the best price for these by exposing them to the largest audience of potential buyers. This means
ebay, for all but the very most valuable of coins. Are you an experienced
ebay seller, with good Feedback? This could count against you if not - people won't risk a large sum of money on a new seller offering gold coins. That screams, "scam!"
Take stock of things. Are you an experienced
ebay seller? Can you take quality, gradable pictures of these coins? By that, I mean this:

...or something fairly close. Do you have some time to invest into maximizing your return? It'll cost you between $25-100 per coin (depending on speed and vendor) to have one of the
TPG's grade these coins, and the turnaround ranges from a few days to a few weeks (time costs money - how fast do you want to go?).
If these coins are truly excellent, a higher-level venue such as Heritage Auctions, the largest in the business, is in order. Another possibility is a consignment with an established
ebay seller - look no further than CCF's owners, who sell on
ebay as "Bobby131313," for this possibility. They won't do you wrong.
It's most important for you to now answer the question you asked,
Quote:
but what do I know.
We stand ready to help you answer that question.