Makes since, and yee I mean it's harder to continue working on something you don't see the 'End' of it. I will say maybe try if you can to break down (what left to do before the system will be function) to a small steps 1,2,3... And if you know(more or less) what need to be done in each step in order to finish them, add it too. then even if those steps will take a bit time, since they have a "Visual step by step" for the goal, it will be easier and more fun to join in.
Again that a least what helps me a lot well working in the past year on my big/long project goal (art, farming system, time, day-night, mine, fishing, ABS battle type system, NPC, dialogue, Animation tools/weapons, Story Eventing+some camera work, and more...).
Sounds like you have a good plane, I can't wait to see this GDU system get back to life.
Best,
TGA