Myself and wifey were picked up from hotel in nice jeep with AC on to the max. They provide a driver and tour guide for $80! We were brought to each temple and the guide would get out bring us around while telling us the history of inscriptions and statues. When finished he would call the driver who would then pick us up at the entrance in a super cold car with cold bottles of water. This is an absolutely luxury as the heat/hum is so intense.
Would highly recommend these guys. Our guide "Mr La" knew all the best photo spots too. Making sure you got loads of pics with no one else in them as it is quite busy.
Tip: bring a spare shirt as its so hot and nice to change half way through.