So, to be more precise, I want to create something like this:

-I want to enter the minecraft lobby and when I press the singleplayer and create a new world, the present map would be the same over and over like modpack such as crashlanding or skyblock.

I notice was well, if I create a chunk(s) in MCedit, and remove all the other and save the map, when I enter the save file, the game would keep the chunk i design but fill the void ones with random blocks, I wonder how can I recreate a world starting in the same spot over and over again but having certain chuncks every time I start a game and let MC fill the empty ones, adding the same custom base every time but give the random terrain of the empty chunks recreated by MC.

I would be grateful if I could have some hints/help on what to do on config files or mods that can make what I want!