Congrats! Nice unit. Very similar floorplan to The Coachmen Prospera I had, affectionatly referred to "old #3" heehee. Really liked that floor plan. As smitty allutted to, leaks will wreak hovac on a travel trailer, so get yourself some dicor lap sealant from your local rv dealership and go up on the roof and reseal everything. Even if it looks good reseal anyway. A small pinhole can ruin a wall over time. The designers are very nice trailers, you will enjoy it.
As for the break away cable, I installed a long eyebolt thru one of the holes in the bed mount rail. Put a hook on the end of the cable and I can reach in and clip it on while i'm plugging in the electrical. Used to hook it to one of the hitch pins that hold the hitch head in, but being a dually I always had to crawl up on the tire to as I couldn't reach over the larger fender.