I think cariboocreek has it right, just get a tape measure and measure the outfit when hooked up? I did that with my truck, FW and boat all attached at got about 73' so I know how long my "train" is. Don't worry, I don't try to pull into the campgrounds with everything hooked up, I do drop the boat at the marina before setting up my FW.
2012 GMC 2500HD D/A Crewcab
2012 Jayco Eagle SuperLite HT 26.5 RLS
2009 Crestliner Superhawk 1900
2013 Polaris Sportsman 550 EXP
2008 Polaris Sportsman 700 X2