Thought I'd update this....
We took possession of our new '13 351 RLTS a couple of weeks ago and needed to move to a different spot at the storage lot due to the length (It's a beast!). We're now "pretty close" to the lot's dump station. I already had two 10' Sewer Solution discharge hoses and adding a 3rd (30' total) allows me to dump my tanks from my storage spot. I can also reach the fresh water by adding a second 25' drinking water hose. I doubt that a slinky would work over a distance of almost 30' (unless the run was downhill). With the SS it's no problem.
2013 F-350 CC SB 2WD 6.7PS
2013 Eagle Premier 351 RLTS
-SOLD- 2012 X23B
-SOLD- 2003 Ford Expedition 5.4, Bilstein shocks