Since Heroes premieres tonight, I thought I'd go ahead and address where Peter stands
Really it's not complicated and it probably doesn't really need to be said but I thought just in case, I would. Peter is obviously still engaged to Sasha. All the things that happened to him this spring/summer happened pre-s2 finale but post him returning. He and Sasha are also in the process of adopting Henry. They've also just bought an apartment in New York City.
As far as canon, short of Peter getting a new girlfriend or having amnesia again, he will be following canon. And I swear to God if they send him all over the damn world again, he's dragging Sasha and Henry with him.
Right now, he is in Texas with Nathan. Sasha knows he's here, alive yadda yadda etc. Uhm...I think that's it. I'll post more of these as major things happen and I think it needs saying.