Cost, safety and enjoy
I suppose it depends where you’re flying from but I always thought Southeast Asia was the cheapest place for backpacking.
It’s so easy to travel around and between countries, on trains, buses or even flying, and there’s a huge number of backpacker hostels for low-cost accommodation. Street food throughout SEA is super cheap too.
I did a route from Singapore>Malaysia>Thailand>Laos>Vietnam (from there you can get to Cambodia if you have time – we missed it unfortunately) and had a great time and met loads of cool people.
Hope this helps – happy travels