For the black/gray streaks on exterior I used about 1.5 gallons of Simple Green and a scrub brush on a pole... but even better is a cleaner called "Spray Nine" that's hard to find anywhere outside of Ace Hardware. Phenomenal cleaner. Afterwards, I was advised to go to the local truck stop and I hear they'll hit it with a truck wash for $50 or so that shapes em right up.
The two gray hoses, yes - the plugs go in the end, they're drains. I have new holding tanks I'll be installing VERY soon, got a great deal on eBay and will need a little fabricating for brackets - but otherwise should be ok. I'll post later once I get em installed. Black will go under stool in back, and gray will go over axles or as close as possible. Trying to put clear supply under bunk bed inside. we'll see how that works, looks like a great fit.
If you did your gray/black holding tanks, posting tips or etc would be helpful for the many who have yet to complete this task...
