Where will season 6 start off?

Normally, about two months pass in the House world between seasons. So this means either House will be in the facility for about two months (not entirely implausible depending on the severity of his mental issues) or TPTB will pick up season six directly where season five left off (unlikely in my opinion, but anything's possible).

it's not like the can avoid the whole house in a Psychiatric Hospital plot so i think they're gonna start from there

I think that is in the Psychiatric Hospital

In the interview with DS, he said that he put House in the loony bin for a reason. He is going to show everyones reaction to him being in there. And he is gonna show how the team deals with him in there...I believe( think) that maybe one or two episodes are going to be shot in the phyciatric(sp?) hospital