Turtle Rigging Help?

Hi I am new here and fairly new to Maya and am currently doing an assignment where I have to do an animation which involves rigging a character I have created.
I have finished modelling it and did the skeleton but need some help with some expressions so it could move one foot and another one follows. My main problems are that I when I move one leg the back legs do not follow in motion and gets left behind and another question : when I bind the skeleton to the skin using a rigid bind how do i keep it from not deforming the shell when I move legs and neck.

Thanks to whoever helps

To keep them moving together you could probably use locator's and constraints or connect translation values. You can bind only selected faces(select those faces that you want deformed).

thanks for the help but one thing I still dont get is what expressions I can use to have a walk cycle with the four legs so that the pelvis root is centered with the leg movement.

For a 2 legged person walk cycle I put this code in the root of my skeleton

transRoot.translateZ = (lfoot.translateZ + rfoot.translateZ)/2;

Thanks again and Sorry if I am not really clear with my explanation