Game World Editor?

[Draxxar67]

(Been working on my own take on this while checking back here).... After a few attempts to build the various rooms I noticed that, for me anyway as a longtime hobby programmer, it looks like it will be easier to simply build the game world editor program first and then later the game itself. That way it'll be easier (?) to view, manage and update the json files while getting a visual idea of how these screen/pages are going to look like. and all fit together.
So the big question here is, wouldn't it be a better idea to build the world editor first? Because right now I'm seeing a problem here right away, in that the json files here don't seem to logically connect with something like a room number and pointers to/from other room numbers and room class types. Plus back-connector data as well.
Just for as an example on this, a simple "hit spacebar to continue" screen should have "nextRoom" and "prevRoom" data in it, esp. helpful for later bug testing. and of managing and updating the game world itself. To clarify, I don't mean the next or previous element in the json file but the actual room paths back and forth, because those may be different and in a game editor it's going to make more visual sense to page through how the player's going to see these screens.