The MK direct bus from The Settlement Depot was installed during the covid protocols because the small boats to to WL and CR were discontinued completely and the big boat to MK was running at a reduced capacity (distancing, etc.). The bus runs for the other Disney theme parks (Ep, DHS, AK) all leave from The Outpost Depot.
The internal bus lines (Orange, Yellow, Purple) all run between the two Depots through the interior of the Fort. The new Tri-Circle-D Ranch facility is across the road from the Settlement Depot.
So if you're coming from MK headed to TCD, take the direct bus and walk across the street from the Settlement. If coming from any other park or driving directly, you'll arrive at the Outpost area so you'll need any internal bus (or walk) to get down to the lake end of the Fort where TCD is.
Hope this helps.
Bama Ed
PS - personally I like the addition of a 2nd Disney way (bus) to MK to go along with the 1st way (boat). There are times in bad weather/high winds when the boat doesn't run and then they have to scramble to add ad-hoc bus runs. So have a constantly operating 2nd method (that can be added to with more buses in bad weather) helps build expectations of the MK transportation available.