Don't fly, travel overland, that's the most interesting part of the trip, especially the remote areas near borders...
The worst is to book this round-the-world ticket, where you have to decide in advance how long you'll stay at each point. We travelled around the world for 1 year and ended up staying as much as one month in one place where we'd planned to stay 1 day, or literally flee out of countries like Malaysia after 2 days.
I traveled around the world on an RTW, and while we did have to pick the cities in advance, the dates could be adjusted at any time. So we used the flights to create the backbone of the trip, and found local* transportation along the way. And we adjusted the dates quite a bit.
My dream trip is Houston to Singapore overland via a transatlantic crossing, the Trans-Siberian Railway and trains/buses across Vietnam, Cambodia, Thailand and Malaysia.
Theoretically I could return via Central Asia and the Caucasus but I haven't figured that part out yet.
Some part of Malaysia make you want to flee ASAP (KL, Kota Bharu), but there are some great parts too (Pankor Island, Perhentian Islands, Taman Negara)!
The worst is to book this round-the-world ticket, where you have to decide in advance how long you'll stay at each point. We travelled around the world for 1 year and ended up staying as much as one month in one place where we'd planned to stay 1 day, or literally flee out of countries like Malaysia after 2 days.