Hi!
We are happy to help you with any questions you have, but the tast to describe the whole CM experience in a few sentences is a bit too much for me.
But I think I might be able to help a bit with your last question: There are no fixed exchange rates to and from in-game currency, since this currency is not a true substitute currency, and you will not be able to use it for most "real" purchases (food, gear etc.) but mostly for game-related purposes: Gambling for IG currency, hiring mercenaries, paying a healer and so on.
AFAIK there is also no way to buy large amounts of Mythodea currency, most of it will be distributed in-game as well. A lot of players also use and accept other coins from other LARP events, and you can often buy these for rates of about 30 cents per coin (copper, silver or gold that exchange 1:10 is a widely used system here), but these are, in a strict sense, not "official".