I just let Gandhi out of his viv and let him run around as much as he wants. He'll even climb the stairs now!! When he was a baby I used to cover up any small spaces that he could go under so that I didn't loose him, Like under the sofa's etc but now I just let him out and he has great fun sprinting from room to room - I don't let him in the kitchen though - Too many things to go under! I think this is the best way to let your beardie get exercise ......
You could just allow your beardie to roam in a closed off room of your house that the dogs or cats cannot get to. I have a dog and cat and this is what I do. Works great!