Housebreaking and biting

Question
I adopted a lab/beagle.  He is about 4mos old.  He constantly wants to bite at EVERYTHING.  I give him nylabones, chew toys, but if you go to pet him or play he just wants to play bite.  Second question, he does very well in his crate and if you are in the appropriate room where to door is for him to got outside he will stand at the door.  The problem is, if you are not in that room he does not know to bark , scratch or communicate to you he has to go out and has an accident in the house.  I thought about the bell, however he will just mess with it and bite it 24/7.  Any suggestions?  Thanks

Answer
Young Labs, which I know best, and other puppies tend to very bad about
biting.  You see a litter of them, and all the ones that are awake are biting
another one or themselves.  I am not even sure they realize that when they are
alone, if they quit biting, they would quit being bitten.  At 3 to 4 months
they are getting their adult teeth, and it seems they spend every waking
moment biting or chewing.  One thing you can do at that stage is to knot and wet a piece of cloth.  Then freeze it.  The cooling will soothe the gums.  Only let the puppy have it when you are there to watch it.  I maintain a Lab's favorite chew toy is another
Lab.  Otherwise they settle for any person they can.  They keep hoping to find
one that won't yelp and jerk their hand away, or growl "Bad dog." and clamp
their mouth shut.  Then offer a chew toy.  They keep trying despite hundreds
of corrections.   Another good technique is to quit playing and go away.   Be
sure to praise them when they are playing nice and not biting.

You just have to keep on correcting them, hundreds of times, not dozens.
Provide sturdy, safe toys such as Kongs and Nylabones.  Avoid things they can
chew pieces off and choke on them.  Keep them away from electrical cords.
Crates are essential for most young Labs and other dogs.