I agree that we need to see Mac's place. I see it as being very neat and tidy (he was a Marine after all!) with more military photos and also one or two photos of Claire. In Blink he said he kept the beach ball, but in Sweet 16 he gave Reed some photos of her, so I would guess he has one or two framed ones at home, maybe of their wedding day or something. He'd have his guitar there too of course. I think his apartment/house must be the one he shared with Claire, because that is the address Reed was given for her in Consequences. So it would make sense that he wouldn't take Peyton there because it might feel wrong to have his 'new girlfriend' in the room he once slept in with Claire. But he lets Stella come over because she's his closest friend and the most important person in his life. I also think Stella used to come over when Claire was alive to talk to/see Mac, so he probably feels comfortable having her over. I mean, he did offer her his spare room in RND!