potty trained

I think Lizzy is potty trained now. she hasn't had an accident in 5 weeks and goes and sits by the door when she wants to go out.  I would like to give her more freedom in the house. I currently keep her on a long tie out but every time I take her off it she goes bonkers jumping on the couch and chewing on the pillows and chasing the cats. after a few minutes of that I tie her up again for a little while and then let her loose again. if she starts attacking the couch again I put her back on the tie out.  I'm hoping if I keep doing that she will get the message that she can be loose if she behaves. am I approaching this wrong.  she is only 5 months. it's been a long time since Timber was a puppy and I never had any problems with him. I think he was born well behaved but Lizzy is a bit wild.  another problem I have is she won't go near her doghouse. she is mainly an inside dog but she loves to be outside and will run around like a nut with her squeaky football in her mouth. I got the doghouse because she loves her crate and I wanted her to have a comfortable place outside to rest if she wanted to stay out there. I put some treats in it and she went in and got them and that was it.  sorry this is a combination post but I didn't want to post in two different places.