I've used several hoses for our Oliver. I threw the Rhino hose in the trash can and bought a Valterra D04-0450 Viper 15' Sewer Hose Kit from Amazon. You can get it either at Amazon or Camping World. I also bought a 10 foot Valterra extension hose and attached it. Now I have a 25 foot sewer hose that stays permanently attached to the Oliver until I take it off when I get home for cleaning. I have never had the Valterra pull apart like the Rhino. Unfortunately the part that goes into the sewer hole will not fit into the rear bumper compartment so I just detach it and keep it in a breadbox in the rear storage compartment until needed. If you do a little research, you will find out why the Valterra is much harder to pull apart than the Rhino which scared hell out of me every time I used it.
For water hose and black tank hook up, I bought from Home Depot three Garden Hose Quick-Connect Kits. They cost about $7 each. I screwed the male ends into water connections on the trailer black tank, city water, and water tank connections and leave them permanently attached to the trailer. I leave the female connected to trailer male section until I start to use it, then disconnect the female - screw it onto the water hose, then reattach it to the trailer, then turn water on. The Quick-Connects make using water lines very, very easy. When traveling, I screw the black dust caps onto the Quick Connects. I'm sure your quite confused by my pitiful attempt to explain all of this, but if you purchase the Quick Connects and play with them for a few minutes you'll get the idea.
Can't make any suggestions for rainy days other than to say that in 2013, we bought a new 40 foot Tiffin diesel pusher which we had for about seven months, until a very large semi totaled us. We bought an Oliver Legacy Elite II and have traveled for about 40,000 miles all over this country, including Alaska. Ask the Oliver folks and they will tell you this is true. We loved the very expensive Tiffin, but my wife and I love the Oliver much, much more.
Sometimes at our home in Florida but today we are in Wyoming.
Hap