Other stands toilets are tiled and finished to a decent standard. Are you telling me your toilet at home is like a factory broom cupboard? After all, you're only there for your body functions.
Check the rows from O down to A. I'm sure you'll find something. I'm like you, cannot manage the steps, standing throughout the game and need a cheap option.
Despite what a lot of Nsc says, not everybody in the North stand actually stands. If you get seats in N1G or N1F (nearer the east stand) you will be able to sit throughout the game and see everything.