Hey Kai, thanks for waiting, these are some great plans, these no-canon houses give some flexibility to get creative and I house tests you've come up with.
I do wonder how abandoned the lands would necessarily be. Though we know that the Starks ended House Amber at some stage, it might've been hundreds of years ago. Given that A World of Ice and Fire mentions them when describing the Starks reign as the Kings of Winter, they might've been destroyed before Torrhen Stark bent the knee to Aegon, which was at least 300 years ago, which would be plenty of time for another strong clan to come along to claim control of them.
So, suffice to say, I think you've got scope to add some more active, healthy communities/hamlets/holdfasts to show the area is still used and occupied after the end of the Ambers. Possibly near the stream inland around the number 4 on your map. Otherwise I think your proposal could still work if you'd prefer to focus on the ruins, we can work something out either way.