I'm not a modder, but this sounds like adding a completely new function/mechanic to the game.
Something simpler might be to make beds and plants snap-able.
I really hope this is possible. Trying to line stuff up manually is too tedious for me.
For now I just convince myself there's a natural beauty to the randomness of it all.

It would be awesome to have a grid pattern on the ground when in build mode or planting mode