though it's not "North America" thought i might get some feedback to the question:

Where would one go for the best offshore fishing in western mexico?? Cabo, puerta Vallarta, or mazatlan or am i missing a lesser known gem.  billfish and tuna would be the prime targets. I'd like to take my dad down for the trip of a lifetime-any feedback would help-thanks

How about the Cayman Islands?  or Coasta Rico?  Good luck!  Would you think about adopting me?  I never get tired of catching those things but my body will not take it anymore.  I guess if I knew I was going to live this long I would have taken a little bit better care of the old carriage that I am in everyday.  Great fishing you can't go wrong!  Unless your Dad is like mine.  I look my Dad inshore once and there were 2-3 seas and he spent the day explaining to me we weren't going to catch anything since we did not bring any crickets!  Hope you and your Dad have a great time!  Uncle Tom

GOD BLESS YOU U.T. YOU LIVED THE LIFE OF A TRUE FISHERMAN AND GOD TAKES CARE OF PEOPLE LIKE YOU BECAUSE YOUR A GOOD MAN WHO PUTS FAMILY INFRONT OFF MONEY THATS A REWARD ONLY GOOD MEN CAN POSES .GOOD LUCK IN THE FUTURE AND TAKE CARE OFF YOURSELF.P.S GOD IS A FISHERMAN TO.

Look into Guatemala,
Sailfishing, Rooster fish (inshore). Its common to get 15 hook-ups a day on sail's. Not too expensive .

Well unless you are in Calif or one of the western states what about SE Florida, the tuna are running hard now and Bills are always around