The starboard tank is in the genny bilge outboard and above your starboard battery bank. The hoses and fittings are accessed through a cutout under the rear galley bench seat. The hoses enter the tank basically under the staircase from the salon to the galley. The cutout is on the back wall of the outboard compartment under the seat. It's hard to reach under there, but possible. I got the specific size of large socket that fits the "3/4 full" sender head, clipped the copper tube off and unscrewed it with the socket wrench. It took a big breaker bar on the big socket wrench and a day of letting PB Blaster soak in, but it worked great.
The inlet hose to the starboard holding tank comes only from the mid-stateroom head, with the head pump in your starboard engine room. The forward head and the aft stateroom head empty into the forward holding tank.
BTW - Depending on the age of your boat, you may want to replace the bronze pumpout tubes inside the holding tank too. They're bronze tubes and eventually they rot out near the top, so when you pump out, you only pump out about 10 gal of the 100 gal tank. Then your tank is full and your heads backing up and you wonder why. To replace, you unscrew the old bronze one and make an identical one from PVC bought at Home Depot. Hatteras is now using PVC for this on new million dollar boats. It's relatively easy to do the forward tank, but a major PITA to do the starboard tank. I did it, but it took many hours.
Doug Shuman