5/11/13:
I've been meaning to send you an update. River is doing really well, and she's a total sweetheart. She's still got a lot of puppy energy, but we're working on not jumping and on pulling less on walks. She likes to run so I've been doing a little jogging with her each morning to help get her energy out.
The cats don't love her, but we haven't had any major incidents yet. River wants to play with them, but is a bit too rough. I keep a close eye on her when the cats wander by, and they aren't shy about standing up to her.
River has a bit of separation anxiety, but she seems to be calming down as she feels more secure with us. I can walk out of the room without her crying or barking now which is big progress from a couple weeks ago. I'm hoping to crate train her, but she is pretty leery of the crate right now.
All in all I think things are going very well for three weeks in! I'll keep you posted as she continues to settle in.