Mine fits perfect in the 8' bed, it is a 4 person cart, but has a foldable rear seat.
I know your question is about a 6 foot bed, but I would hold off for an 8', they are much more usable and worth the wait.
I know with my TT, if I lower the tailgate there is no way I could drive as it would hit the tongue jack, but all set ups are different.
2017.. Prime Time Avenger. 32QBI
His.. 2011 F-350, King Ranch, 6.2L. Crew Cab, 4x4, 8' bed, SRW, 11,000 GVWR
Hers..2008 Ford Expedition, King Ranch Heavy Duty Tow, 3.73 gears
Sold.. 2005 Star craft, Travel Star 18SB
Sold.. 2013 Keystone Laredo, 291