Towing boat question

We have been towing both our fifth-wheel(FW) and a boat behind since 1993 when we bought our first FW. Have towed up to a 5,000 boat/trailer combo behind our FW but are currently towing a Jayco HT 26.5 RLS and a 19' Crestliner Super Hawk. We have never had to back this combo up and hope to never have to do so. We put the boat in the street prior to hooking up the FW and then back the FW up to the boat, using my wife as a spotter. Has worked great for 20+ years. When we get to our fishing spot, we drop the boat and then go find out camping spot, drop the FW, have lunch and then take the boat out fishing. You shouldn't have any problems with your set-up at Flaming Gorge or Lake Powell, there's plenty of room at those lakes. Our set-up is about 70' more or less and tows just fine behind our GMC D/A combo.