Make your way by train
You might be thinking, buses and trains are tiring and too slow.
Well there are many fast trains in North America, and almost all of Europe, China, Japan, Russia and even others. I personally prefer the slower trains as they are cheaper, offer tourist packages in many countries and allow you to see a huge part of the countryside that you may not have time for.
A plus side of trains is that if you take the slower night trains, you can get a sleeping compartment and sleep all the way to your destination.
While travelling from Vienna to Budapest I was told the stories of sleeper trains being raided, in central and eastern Europe,by thieves, and people’s item being stolen from compartments.
Luckily I didn’t experience this but got to know tricks to keep my expensive belongings like money, passport, phone in a bag inside the shirt and use any bags as pillows. I tried the bag-as-pillow once, and it was not as bad as you may think.
In any case even if you don’t take a bed, there are reclining seats in many trains, especially in France, so make full use of this!