Mine has a sewer connection and valve at the rear for the kitchen sink grey water tank. I use a cap with a garden hose fitting and run a 25ft garden hose (color is black)from the sewer cap to the campsite sewer hookup. I have a second garden hose for distance.
The other sewer connection is middle of the 5th wheel for the black and grey tanks for the bathroom. I have two 20 ft sewer hoses in case I need distance.
On the end of the sewer hose I have a fitting which goes into the campsite sewer hookup and it also has a garden hose connection for the hose from the kitchen grey tank.
Simple setup with flexibility.