Currently I can only suggest to use the
ColumnWidth property of the TreeList's column, like so:
ColumnWidth = "*"
The behavior of the star is different than in the GridView - the star will only size the column in the beginning but if the given space is resized the column will not shrink or grow.
As for the last two columns I can suggest choosing a larger width (or MinWidth), something like:
ColumnWidth = "120"
You are right that the GridView version of the TreeList will inherit the GridView's features.
the Telerik team