Ad- First, forget your mail in idea. Las Vegas doesn't accept bets that way and they really don't accept them in person either. This city got out of the gambling business a long time ago.
As Fish said, jump on the internet and find the best price you can on your team and open an account or two. You'll find much better odds than the rip off sportsbooks would give you and you shouldn't have any problem getting down what you want offshore. Las Vegas is a complete has been in the sports betting business.