Just having a corporation registered in Nevada does not prevent you from paying yoour local state taxes. This is especially true if you have ofline customers. If you have a customer in say texas and you live in Texas but are registered in nevada, you have to register the company in Texas as a foreign corportion. This is why it is sometimes better to just register in your own state because filing fees are going to be the same as registering in your state in the first place.
If you register in another state, that does not automatically make you legal in every state.
Check the regulations for your state before assuming that Nevada is the way to go. Like for me, I would pay to register in Nevada and then pay to register in Montana (which is cheaper than Nevada). Now if you want Anonimity then registering in Nevada is the way to go.
Foreign residents can own corporations in any state. You will have to check with that state to see which format will work. For instance in Montana a foreign entity can not have a share in an S corp. Those little things will trip you up.
As far as a registered agent goes.... All they want is a live body within the state that they can deliver the summons to.