Welcome to Chaz!
Huskies can be difficult dogs to train, they tend to be more independent than other breeds and really choose to do what works best for them. The key to training huskies (and really, any other breed as well) is to determine what is rewarding to that dog and then use that as a reward. Sounds simple.....
For example, you know that your dog likes chewing and tearing up stuffed things. If this includes the couch and other furnature, then keep in mind that tearing up the couch is fun for her, and she's going to continue doing what's fun. So you'll have to use good management when you're not watching her to make sure that she doesn't reward herself for doing something that you don't like. This means keeping her in a crate or in a dog-proof room while you're not home so that you're sure she's not tearing up anything she's not supposed to.
That said, tearing is an instinctive behavior for dogs - some dogs NEED to do this as an energy outlet, just like some dogs really enjoy playing fetch and some dogs really love chewing on bones. So you can use this as a reward. Whenever you have a particularly good training session, or when she does a particularly good behavior (like coming when you call her), go to your stash of new toys (the 89 cent ones from Wal-Mart), and give her a brand new toy to tear up. This will be hugely rewarding for her, so only give it to her when she's done something that earned a huge reward. Otherwise, make sure that all toys are put away where she can't find them, or she will reward herself for bad behaviors.
Teaching a dog to stay in the back of a pickup is not only extremely difficult (since you're not there to reward when they do it, and you're not there to correct when they get up), it's also extremely dangerous due to the fact that she's not physically restrained. It's much safer to either let her ride in the cab with you (where you CAN teach her to stay in the front seat if you like), or put a crate in the back of the truck so that you know she'll be safe and will stay.
As for your other questions, first of all, stop training with treats physically on you - in your hand, in a bag on your front, etc. You are teaching your dog that doing behaviors you want are really only rewarding when you have a treat in your hand - otherwise, she doesn't get a great reward, so why bother? This is bribery, not training. Instead, put the treats on a nearby table or counter so that you can reach them, but don't ever have to keep them in your hand.