View full site option for users

I have been trying to get a view full site button for my blog to allow users to switch between a mobile and desktop version if they want to. It would also help me in testing. I have gotten as far trying five different plug-ins which were supposed to be able to do this and I did manage to get a view full site button on my footer with two or three of them, but it only got me to the mobile version of my responsive theme (Catchbox). My husband says that I need to have two different themes to switch between and he seems to be right. But all the themes seem to be responsive and I think I would need a non-responsive theme to try that. Even if I could find a non-responsive theme that I like, I am not sure what it takes to manage two different themes. Has anyone done this without coding (which seems more breakable to me). Thanks so much