I would not set foot in Mexico. Ship the bike down

Before I post, please recall I've had an adventurous spirit too through life and I'll take you one step farther.  I was an adrenaline freak in my youth that would rather fight than have sex.  Also keep in mind, in this thread I've been quite supportive of your endeavor for even if you fail, as long as you don't get yourself killed, its going to be an adventure of a lifetime.  Of course, its not going to be easy.  You aren't looking for easy or you wouldn't be doing this.  That being said, indeed it is playing the odds and that means not taking unnecessary risks.

IMHO, your motorcycle ride is unnecessary risks.  This is coming from a guy who has traveled the world for business and I don't mean tourist areas.  Some of the things posted in this thread makes me laugh like Cancun is Mexico.  All hells on Earth have little havens in them.  What I'm going to tell you is Mexico in transition and its not good.  In the last five years almost every American I know that worked and lived there has left.  In fact, even the guys who lived in the US and only travel across the border to get to work have quit their jobs. Even more, most of the businesses I did business with are moving out, one at a time.  I'm talking nice places to not just hell holes like Juarez.  Its not just the crime but all the corruption that comes from the money associated with the crime.  

The internet is not real life.  Those who disappear there don't post afterwards.  Only the ones who make it do.  In today's Mexican climate, I would have been a lot more comfortable seeing you post you've banged heads than you have rivers or mountains.  

Whatever motorcycle you have, if you can't buy one there then keeping it is going to be more hassle than its worth.  I haven't been in a 3rd world country, they don't sell more bikes than they do cars and I'm talking unheard of prices compared to the US.  I'm sure you are convinced, you can make it.  You probably can.  All I'm saying here, it is an unnecessary risk and that is not the way to start any adventure off.  Risks are coming your way without asking for it. That's life.  You have a lot to do when you get there.  Being rested and not looking like a wore out bum can be very important to accomplishing your tasks.  

Now if you tell me you can travel that far in hot weather on a bike and not be wore out looking like a bum, I'll know you haven't done that and are taking advice from others who haven't.  I've been riding bikes for over 40 years.  In fact, I'm going riding after I type this.  

What you are proposing sounds like you plan to go catch rattlesnakes in the desert before you before you go kayaking a class V.  Maybe you won't get bit, probably won't, but if you do, there goes the class V trip.  In Mexico, I may even be so bold as to think I can work a deal with a cartel but there's no making a deal with all powerful Sheriff  Jose that figures somebody in the US will want you back.  He has one goal only, pad this palm or you stay here a while, a long while.  

I advise you to stay focused on your goal.  Its going to be a hell of an adventure without adding unnecessary risks.  Having moved to seven states in the US coast to coast and that's mild to what you are planning, you have enough flipping the coin coming your way.  If $400 to ship something is too much money, man, you aren't prepared for this adventure.   I've spent that much bribing officials in Mexico in one trip.  That place has just been turned upside down in the last five years.  

Tj