If you're going to wear a backpack, keep in mind, most of them aren't made to withstand high wind resistance....so don't get a 5 buck spiderman backpack and expect it to last..
Other options are, tank bags, saddle bags, tail bag.
Bungee a duffel on your passenger seat, or on your rear fender, smaller bags can be bungeed on your forks (make sure the bags won't get hung up in the wheels).
If you have a passenger, you can even fit a bag between you and her (or him, if that's your sort of thing...I'm not judging).
Other option, have your crap shipped to your destination and ship it back/throw it away when you're done and ready to return...
OR....take less sh*t...