A couple random thoughts...
-- The head sink will be relatively easy. There's a carpeted panel under the head door that easily removes. Just feel "into" the carpet for the screw heads. That will give you access under the head floor to help run the line.
-- The cockpit sink is also easy. Same deal - feel into the carpeted panels to remove the false back wall. Only going from memory here, but you probably have to first remove the "box" that boxes out the underside of the sink.
-- The galley sink is going to be the harder one - at least to try and get it to the under-step sump box. You might be better served to put a sump box under the sink and then run the output hose to the bilge via the port-side wall (behind MDP and port-side of mid-cabin.... or maybe just decommission the galley sink.
-- The head sink will be relatively easy. There's a carpeted panel under the head door that easily removes. Just feel "into" the carpet for the screw heads. That will give you access under the head floor to help run the line.
-- The cockpit sink is also easy. Same deal - feel into the carpeted panels to remove the false back wall. Only going from memory here, but you probably have to first remove the "box" that boxes out the underside of the sink.
-- The galley sink is going to be the harder one - at least to try and get it to the under-step sump box. You might be better served to put a sump box under the sink and then run the output hose to the bilge via the port-side wall (behind MDP and port-side of mid-cabin.... or maybe just decommission the galley sink.