I wanna backpack europe and america some day too but prolly after I graduate uni.
Anyways, I haven't actually backpacked but I hope what I have to offer is useful. Not necessarily about places to visit, but extended travelling in general.
1) Thoroughly, very thoroughly, forumlate a plan for safety measures and make sure people know where you are at all times
because shit happens you know? Try not to stray too far from your plans unless you're partner is with you. Also be sure you are prepared for anything that may happen too (wild animals, getting lost, injured and so on), be sure your first-aid knowledge is up to date etc. If I were you I'd go with maybe one other person who has the passion to travel and visit new places and venture into the unknown and spontenous to make it not only fun but safer too?
2) Make sure you have essentials (water, food, clothes, money, place to stay) at all times and make sure you have enough/more than enough. Fuck the weight you'll be carrying on your back, your survival is more important.
2) Research on places to go. It's important to make your experience the best it is and to explore as much as you can so do research thoroughly on places to visit - people seem to forget about places that isn't iconic etc. when it comes to travelling. Don't forget about nature/sceneries, historic locations (like visiting former death camps in germany that are open) extreme/active activities and even things like shopping, museum, theatres etc.
3) Do extensive research on areas you're going to be in. Be sure it's a good time to visit the area. Be ready for extreme climates. Have a map with you incase you're lost. Try to learn the basics of their native language if you can cause it'll make things easier.
idk i'll add some more to the thread if I can think of them but this is all that's popping in my head atm...