Jaime, it's best to let those with the Sherpa chime in. I would expect the Sherpa to be too little a bike for that kind of trip and have the comfort and performance you would want. That said, there have been folks who have done it on smaller bikes. Can't say what their comfort was...
If you are traveling slow and easy, with a light load (rider and gear), then it might be okay. My wife decided to pass on the Sherpa and got a KLR650, just so she wouldn't be disappointed when we head for Alaska in a couple years.
Life is a mortal adventure. Don't avoid all the risks.
2005 KLR650, ready for the world
1999 KLR650, badly in need of TLC...
1998 Honda Valkyrie Tourer
2001 DRZ400e, already broken... in