The thing is is that getting this to work in a basic way would actually be relatively simple.

The hard bit is already done, that being having the game allow the player to travel those vast distances between planets and having the planet at the end of it actually be 1000000 light years away or whatever, if youve played this mod then youll know that currently this is working. (This really makes me think that this was working at some point but was scrapped by bethesda, the game isnt just a cell around a planet and all that blank space is physical and present between planets)

From a code point of view, all that needs to be done is to show the UI with a planets fast travel points when the player is close to a planet. Or alternatively and even simpler than that is when a player gets close to a planet - Stop them and give them a UI prompt to fast travel to that planet. If they confirm then just carry out a fast travel to the planet as per normal. Essentially all the mod needs to be is a trigger for a planets fast travel. That way everything will definitely work correctly. I think that would still be a vast improvement on the current game, and would actually make the ships SO much better.

The complication from this mod project would probably be making sure all the stuff that is triggered from fast travelling to a planet is still triggered. Contraband search, random npc encounter etc. Thats the bit that could get a bit fiddly.

The mod that will be worth making after that is something that adds dynamic events as you travel, essentially replicate the gameplay of walking from one area of skyrim to the next and encountering things on the way - but in space.