Trophy bucks are found throughout KS. As you most likely know, there is a huge difference in topography, climate and vegetation between eastern and western KS. Personally I would focus on central to eastern KS. Many 3 1/2 year olds will hit the 140-150 range that you are looking for.
Muzzy season can be hit or miss. The bucks are predictable then but if it is warm (which it often is) daytime sightings can be rare. If it is cool, you could kill a good one hunting a field edge or trail leading to a field.
The rifle season is timed a bit late for the rut but sometimes the first few days of the season have some rut activity. The timing of the rifle season saves many big bucks that would normally be cruising if the season started a couple of weeks earlier.
PM on the way.