I have had good luck with a wire type barrier for keeping my dogs in the back of the SUV. With that, I can still open the windows so that they can get the fresh air and not have to worry about them escaping. The only problem I have had with it is to make sure I have a good hold on them as soon as I open the tailgate so that they don't jump down and run off. It's also much safer than the back seat...just think about what would happen if you had an accident while the pup's head was out the window...ouch; or even flying forward to or through the windshield if he's being good and just sleeping on the backseat. It's the same reason you restrain yourself, isn't it?

Maybe to socialize with other dogs, it would be better to go to a puppy obedience class or something, where all the other puppy/dog owners have the same goal as far as socialization. Neighborhood dogs may be expected to guard their people or territories and you would ruin their training by socializing with the puppy.

As far as keeping him off the bed, he just needs to learn that he has his own place, which can be the crate as others have recommended, but it can be any place you decide it is. Just make sure he knows 'no' or 'off' so that you can correct him when he tries to get up and just put him in the right place and praise him for staying there when he is good. Do not give him any kind of attention when he's on the bed. Just move him from that spot and set him down without rewarding or fussing and reward when he goes to his bed.

My Maggie tries to sneak on the bed all the time, but whenever I catch her there and tell her 'off the bed' she knows that she has to get off and find somewhere else to nap (her favorite pasttime).