FREE THE BEAST!!!
Hopefully the Beast is unshackled and roaming the Costa Rican countryside by now.
I have been to Guatemala twice by motorcycle now, without any trouble, including a backpack trip in a remote area. There does seem to be more crime in Guatemala, just judging by stories from other travelers there, but I still think you would have to be very unlucky to have anything bad happen. I know this isn't much help, but I do plan on going back there at some time, so I consider the risk acceptable.
I met you two at Dakar Motos in BsAS. You married yet, or still living in sin? If you make it to Texas, consider yourself invited to San Antonio.