US to Brazil on a BIG bike
While the roads through Mexico (especially the toll roads) are fine for a big bike, and doable through central America, You might have some problems in loading a Goldwing on and off boats. You can fly the bikes from Panama to Bogota, but would have a problem getting from Venezuela to Brazil if you choose the eastern route. Could be a problem with a GW on the boat from Manaus to Belem, and definitely not advisable by road through the Amazon (much dirt and deep mud). The Panamericana is a possibility (longer). Again, there is always road construction and therefore many miles of dirt/gravel.
Panama City, Panama