one of the places where a guide will be useful but you can enjoy the esthetics and devotion sights without one.
i think entry is 50 bhat, better come early before the masses.
if coming from khaosan area, just walk there along the canal, a lovely walk.

The mount itself offers a nice and easy walk up to the summit with very nice views around but the buildings around it offer much more colour and better pictures. If you go early the heat is less and the crowds are less as well. A bit of Disneyland at the bottom but getting surprisingly austere at the top.

We really enjoyed our visit, while you have to climb 300+ steps, they are not steep and mostly in the shade along the way. very easy climb, even in hot weather. The view is also superbe from the top.