just throwing this out there...
You know you will be going through Patagonia in/close to winter, right?
And to get a truck past the Darien Gap will take more time to organize than with the bikes... or will you ship them all in 1 container? Just this could add a month + to your trip.
Both bikes are great choices.
What are "budget accommodations" to you? Remember places with a garage usually charge more than the shoestring hostals.
Sorry to be a 'half empty' kind'a guy, just want to point out some logistical problems you might face. I would love to travel with a friend who had a truck. It would negate allot of issues.
And 16" rims on the truck will make things easier, btw. And a large transmission cooler too, if it is an automatic. Actually, try to find some of the HUBB people that overland in trucks, see what mod's they do that might apply to your trip.
Try to learn spanish before you leave.