Andrew Clements- Things Hoped For?

I just read Things Hoped For, and I absolutely loved it!! I'm just wondering which of the three books in this trilogy (Things Not Seen, Things Hoped For, Things That Are) you liked the best, which character was your favorite, things like that. Also, I haven't read Things That Are yet. Just wondering.. does Gwen show up again? And does anyone know if there's going to be another book in this series? I really hope so... and sorry about the multiple questions :)