Hi,
I am wondering if you need a comma in this sentence.
Sure. We can even climb up to the statue's crown, if you want to.
I'd say you don't have to have one, but you can put one if you want to. By using a comma to show a pause, for example, you might suggest that the final clause is a reluctant concession. eg
I don't want to climb 200 steps, but we can even climb up to the statue's crown . . . if you want to.
(More natural would be 'to the top of the statue')
Best wishes, Clive