Re: F-150 crew cab towing a 5th wheel?
You'd have to measure yourself depending on which trailer you're interested in. Personally, I'd stick with a standard hitch in your case. If you had an F250 with even a short bed, you could slap a 5th on there without problem or concern. The CrewCab has a very low payload rating as it is. Once you factor in the weight of the 5th wheel hitch, wiring, people and cargo your max hitch weight of the 5th wheel trailer itself would have to be around 750lbs or less, which isn't realistic as most, even lightweights are at minimum 1000lbs empty weight.
5th wheels tow a LOT easier than a conventional trailer, but with the added height and weight comes a hefty fuel economy penalty as well. If you had a one ton truck it wouldn't be as noticeable and evena 3/4 ton could handle the tongue weight a lot better. That's all you'd need is to be pulled onto a DOT weigh scale to find your rear axle is 500lbs overweight. Weight distributing hitch trailer would be your best bet here for weight distribution and safety.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!