I won't get too into the plot in case you haven't seen it, but overall, I thought the episode was a good one and there were little signs that Bobby may not be gone. The episode did a great job of showing exactly how much the boys depended on Bobby's information.
Sam got into some serious trouble because he didn't go in there with all the facts. Dean knew the truth, but if Bobby had been there, Sam wouldn't have gone in unprepared. Both brothers ended up being saved by a 14-year-old. I am a little worried that the character of Frank, the not-quite-all-there conspiracy theorist, may be being set up as the next Bobby.
That would be a huge mistake because nobody can replace Bobby. Frank gave Dean some advice and was acting very Bobby-like through the whole episode. The good news is there was a subtle clue that Bobby may have stuck around. In the beginning of the episode, Dean was drinking a beer and suddenly all the liquid was gone, leaving Dean puzzled.
Was Dean on a binger and just not remember or is Bobby back from the grave and thirsty for a little Budweiser. I guess we'll have to wait until next week to find out.