Are you asking at what distance the guild house disappears? It disappears when I get close. If I walk along the shore and under the city from Katla's farm, the guild house will disappear after passing the East Empire Company warehouse.
Sorry I am not sure what you mean by testing from Dragon Bridge, Morthal, and Dawnstart. I confused myself by trying too many combinations and I didn't build an organized test matrix. This is what I have done so far. I have created clean saves at Dragon Bridge, Markal, Morthal, and Rorikstead in addition of Whiterun and Riften. I get the same behavior as mentioned before where the guild house is ok until I save and exit the game. I then start the game, load my last save, wait around for awhile, and then travel to solitude from where ever I was. The guild house will disappear when I get close to it or when I fast travel to the airship.
Here are SkyrimPrefs.INI settings. I don't remember every changing these myself:
fSkyCellRefFadeDistance=150000.0000
fLODFadeOutMultSkyCell=1.0000
I have attached the lengthy "reset" line.
DynDOLOD_Tamriel_JSON_RESET.txt