Living with in law

Ladies my husband and I decided to move in temporarily (a year) to save money for a house. We will be moving in soon (friday) my dad keeps saying "believe me it's not going to work" or "believe me you won't like it". Have anyone did this before and it actually went good?

- I know it might not work but if it doesn't we will move right away. She is hardly ever home and all she asks is for us to keep things clean (our mess). I'm just trying to be optimistic through this. I know it might suck but if we can save for a down payment on a house it's worth the sacrifice. Especially for our baby girl.