"How do you remember to put the cap on the sink drain & turn off the propane
valve before driving off?"

Mine has an 18" length of garden hose on it. I tuck it in the hole on the
front of the propane tank skid plate, and while down there, turn off the
propane. If I used my fridge, I wouldn't have to worry 'bout turning the
propane off. ;>)

bob