I have a 16' deck, beaver tail car hauler that I use to move my 15' NRS Otter. Have taken many 400+ mile trips and it works fine.
To get the tubes above the fenders, I have 2"x10" sideboards that I attached to stakes that slip into the stake pockets, and then I built a 2"x6", outdoor carpeted deck that attaches to the top of the sideboards. This deck is easily removable for using the trailer for other purposes. I sometimes "self-shuttle" by hauling my car to the take out, going home, loading the boat, and going to the launch
I've hauled as many as 3 boats stacked, with all kinds of coolers and dry boxes and other stuff in front of and under the boats. It tows very smoothly whether fully loaded, or with just my boat for a day trip. It is never bouncy.
I suspect that the fuel economy of my truck (GMC 2500 4x4) doesn't change much whether towing a 750 pound trailer or a 2,750 pound trailer. It's just always bad. Being a 4x4, I've never had issues with it hauling the trailer up from steep or muddy ramps.
I've not had issues getting the trailer down any boat ramps, its only a bit wider than the truck, and being longer than many trailers, it is easier to back. That said, I've been backing trailers for 30 years...