Obviously you can, since otherwise no one could have a shotgun. The legal way to transport one may vary from state to state.
Yes, shotguns and rifles can be carried among all the states with not problems.
In checked baggage if you follow all the rules.
Yes, but it must be unloaded during transport.
Get a copy of the all the laws relating to firearms of all the states you will be going through.
The NRA has a website that can answer your question.
All Terrain Armor Transport.
Yes. It must be locked away, unloaded, and kept separate from the ammo.
All states must conform with Federal statutes. A shotgun cannot have a barrel shorter than 18 inches, or an overall length shorter than 26 inches.
In most U.S. states there is no specific minimum age to shoot a shotgun (or any gun, for that matter) but there are laws regulating how old you have to be to purchase one, which is 18, at least in most states, for a shotgun.
it is shotgun because the size of rifle is different than shotgun.
Indeed this possible, most shotguns come with little iron bars which a lether strap can be attached to them which creates a shoulder sling. This is the most effect form of transporting a shotgun ;)
You can transport a firearm in a vehicle in all states - the only variance is HOW it must be transported. If you keep it unlocked and out of reach with the ammo stored separately, you'll be in compliance with all state laws on this.