There are no urbane votes - just low class kikuyus,luos, luhyas and kambas - mostly living in slums - and now increasingly somalis, gusii, kalenjin and merus. Census tribal breakdown will inform the strategy. I think Ruto is making headways into Luhya Land - because Luhyas can see maDVD and Wetangula are taking them nowhere - and Raila is waste of votes.
Yes unless something drastic was to happen - like Uhuru amending Katiba to remove term limits - it very likely Ruto will settle on Kiunjuri as DPORK.
Pundit, votes for Mariga do not automatically mean votes for Ruto on the presidential level. Ruto will get much less than what Mariga got. Those ma-fans will cast their vote to any other candidate. Ruto has no urban following. He will have to recruit a Kikuyu DP candidate in order to get a chunk of the urban votes.