Well I don't know your coach at all but I am attaching a link which might get you in or near the right place maybe? Check out Carl's comment by scrolling down......of course I am assuming Chevy 454's of a certain age may have similarly placed goodies. Left frame rail behind the wheel.....seems very odd but it's worth a check. The other check might be under the dog house.....but what a PIA if it is there.
Where Do I Add Brake Fluid And Power Steering Fluid In My RV?