thank you so much for your replies.

I guess Animas Forks will be too difficult with a rental car although the landscape looks amazing.
I would like to know more about Havasu. Anyone ever been there?

Is it possible to reach Hualapai Hilltop with a rental car?
Is mid june not too hot?
Is there any possibility to take a guide once arrived or should a guided tour be prepared with a travel agency beforehand?

Thank you so much!