The grey tank for the kitchen sink has a crack/leak on the top. Wasn't too concerned as we're setup in Florida for the winter with the valve open most of the time. Occasionally though we would get strong smells permeating inside. The "temp fix" is a camco drain kit with flex tubing - under $10, short female/female hose - $7 and pvc fitting $1.50. Already had the outside drain Y. See the pics.
Flushed the grey as much as possible, closed the valve, added some deodorizer and capped off the drain tube from under the sink. The camco kit now drains to the outside and then into the drain hose via the hose and Y. Had to also make up a short adapter hose from the Y to accept the cap with hose fitting.
This was much easier than dropping the tank! We're heading to a state park in the Keys in Feb for two weeks and will either reconnect the tank or just leave it and feed the hose directly into the portable blue tote.