EasilyUnstpp_ This may be unrelated to the draw distance, instead Tranzit uses the gump system because it is so big. Basically certain assets are stored in extra gump zones which are dynamically loaded and unloaded depending on where you are on the map. An unloaded texture appears black, and unloaded models appear as black boxes. Unfortunately this cannot be fixed.
If you are refering to the pop in that is a different issue. You can change it by first turning sv_cheats dvar on, and then setting these two dvars:
r_lodBiasRigid -1000
r_lodBiasSkinned -1000
You can also set it in a script with setClientDvar()
self setclientdvar("r_lodBiasRigid", -1000);
self setclientdvar("r_lodBiasSkinned", -1000);