Correct me if I'm wrong, but I think xeofox's proposal is to have actions being built rather than actual buildings in most cases.
So the only things you'd physically build would be the sanctuary set and expanding the campsite, and then eventually at a fairly high level making a mud brick wall. These buildings would also ideally have no effect for non-nomads and if possible could be Area of Recruitment as the only buildable things there - so it would be almost pointless or at least not particularly useful for anyone else to capture the settlement, except to keep it out of someone else's hands (and even then you'd need to import all your garrison troops).
As such "find a winter camp" might replace building a governor's villa, etc etc. You'd find a blacksmith rather than building a blacksmith's shop, and so on. As xeofox points out this gives the illusion of representing the real features of nomadic life whilst fitting within the RTW system.
I think this makes a lot of sense.
(PS xeofox; in your description I've assumed by "parking place" you mean a camping site.)