I don't know anything about giving peanut butter, I would not give it to my little guy because of all the added sugars that go into it.
But as for housing I have Whiskers in two habitrail cages joined together and he loves it. The one side is a split two story (will try and load a photo later for you) and the other side is your regular plain habitrail single story cage. Whiskers is constantly on the go. He has made himself a few little nests here and there and it is a guessing game as to which one he is in.
For treats I give him little pieces of dried fruit here and there, he really likes banana chips.
Hope I helped....and I will try for a picture for you tomorrow morning.
