You maybe able to get 30days exempt plus 30 days extension. But as you don't give any information regarding what country passport you have its hard to give advice.
single entry visa tr60 gives you 60 days, leave and get a r entry permit its still only total of 60 days if you left on the 45 day you only have 15 days left on the single plus then the 30 extension when you return. The multi entry you can get the 60 plus 30. Leave come back get 60 again plus 30, do it again just before the Metv expires. The metv can give you 3 x 90 days less 1 or 2 days when you leave to get back in before it expires
you fly in get 30 days exempt. Go to immigration extend 30 days = 60. Then go Cambodia come back get 30 days plus can extend again. Can then fly KL if you want come back another 30 days plus extension