(snip) ...
This maternal grandmother did mention that there were family members of Ashlee's mother and dad who lived on that route she took... specifically Utah and west of Utah (pretty sure that is what the grandmother meant)
... (snip)
this is starting to "click".
last known sighting of melodee was near CO-UT border, while they were headed back west. and it seems unlikely the moment ashlee left her somewhere would happen to be right after that last sighting. we have a range of possible locations between there and wherever ashlee was then sighted without her. and i'm guessing that range runs along the stretch of I-15 from central utah down toward las vegas, overlapping or including the area where grandma says there are relatives.
a line of evidence and line of logic are converging