Hey Fiona, congrats on your new V. I was home with mine for a few days before I had to go back to work. On top of this I'm lucky because most of the time, my husband and I have different schedules. I'm working and he's at home and vice-versa. However there are times when she is at home alone. To prepare her for this time alone, I began making short trips out of the house leaving her in the crate. I started with ten minutes and moved up to the maximum time I would be gone which was basically four hours like you. I might have popped out for a shopping trip or for lunch but each time I gradually increased the time I was away. It seemed to work out well as none of my neighbors have told me that my pup howls the day away. As to the biting, I know everyone says this is a phase and it really is (but that doesn't mean it doesn't hurt!) My girl is five months old now and starting to get some adult teeth so it doesn't hurt as bad (thank goodness.) She doesn't do it as much now though and the sneak attacks (don't know if you've experienced those yet) have almost come to a standstill. Most of the time she just mouths us without biting and it really is an affectionate gesture. Her way of saying I love you and all. But when she was a younger pup and doing it all the time, a good long walk or play period with a ball or a water bottle or some other toy would get her mind on something else. Or you could try a short training session. They do learn in their own time. All dogs are different. But two to four (five minute sessions) a day seemed to work best with Tizane. Her concentration was completely shot after that. That being said once they learn commands you don't have to spend a lot of time on follow up. Except with recall when they are going through adolescence. She can't remember that one at all anymore. One thing I have learned though, If they don't do it the first time, don't plead with them three or four more times. Just put them in the position you want as you are saying the command the second time. As in "sit" (no response) Press that bottom down as you repeat it the second time. Shows them that if they don't do as you say, you will make them comply. It might sound mean but it isn't. It will make a well behaved pup and one that will listen to you the first time.