We are in the same boat!
We have a 2 year old boxer (Samson/fawn) and a 8 week old boxer (Leilani/white). I can't really answer your question on the crate training but we leave both of ours in the kitchen while we are working or gone period. Before getting the puppy we have left Samson out while gone and he has been very good. I come home at lunch to let Samson and Leilani out since my job is only 5 min. away. Samson can hold it all day though. We brought Leilani home at 6 weeks and she's already going to the door letting us know she needs to go outside. Honestly, Leilani is learning from Samson. Samson has been in the kitchen since he was 6 weeks as well. We never used the kitchen as punishment and he doesn't mind going in their. I guess if you really look at it we use the kitchen as the crate to give them more room. Thank God he has never destroyed anything so hopefully it works the same with Leilani. (Lots of bones!) Samson has been to obedience school for two classes but you can't really tell unless treats are present. When we brought Leilani home we just put her down and Samson took to her right away. He was very gently and they get along great. It's been a couple of weeks and now he's starting to lay the law a little and getting a little more aggressive but not in a bad way. He lets her know when he's had enough and what she can and can't have. He's playing a father role to her. At night they both sleep with us. I know people say that's wrong but they are our little one's. We still have to get up once in the middle of the night to let Leilani out. Samson sleeps on the bed, the floor, where ever he feels like it. Hope this helps a little. Take a look at our pictures and see for yourself how good they get along.
Ralph & Kim
The parents of BIG SAMSON and sweet, sweet Leilani!