Look up the State Laws, but in Illinois there is no carry law (YET!) but I can bring my firearms in my car on the way to the range etc. and that is legal.
They don't have to be broken down, but in a locked case or trunk and ammo in separate area. Also, not in the glove box that is easily reached. Common sense. I put my locked range bag in the back or way back of suv.
Indiana might be different though??