Rifle Scopes : Scope and red dot combined ?

I have a AK-47 with a red dot mounted above the gas tube. It works well but is not ideal for longer shots .........or at least attempts. I found a scope that is 2-7 that looks right down the center of the red dot and mounts over the dust cover. 

Forgive the ignorance of the following questions but here it goes.  

Would this be a wise setup/system ? Having the red dot for close shots and being able to add the scope when far shots are needed ? Can the red dot be let on and used or will it be off? 

Thanks 

Be kind its my first post :)