Steve hit the nail on the head here. If you exceed the manufacturer's GVWR
(or GCWR) and are involved in an accident where it can be forensically
determined that exceeding manufacturer's weight specifications contributed
either to the cause or the severity you will be in some expensive trouble.

Just because you're not a commercial hauler does not absolve you of
liability for exceeding vehicle ratings. You can be fined just as severly
and shown to be criminally negligent.

When we were investigating the 5th wheel RV thing last month and looking
into suitable trucks to haul it with, the Dodge 1-ton dually + CTD was
only marginally legal and questionably safe with a 37-footer (Holiday
Rambler Presidential Suite) as we would be operating right up against the
wall of maximum ratings with virtually no margin for safety. True people
do it all the time, even with less truck and get by, but that doesn't make
it safe or wise. Idiots are born every day. In our opinion the FL50 was
the more appropriate truck for that specific RV.

Not really true. With most 3/4 and 1 ton trucks there is a lot of
reserve axle capacity. The onlu difference between current 3/4 ton and
1 ton SRW P/U's is tires and maybe a extra leak in rear and a lable on
door. Chassis is the same otherwise. You have to be a lot more
carefull with 1/2 tons as they have a lot less reserve. GVW's like tow
ratings are more a product of marketing demands than anything because
if you look at a 98 Ford or GM 1/2 P/U you will find that the new
models have less spring in the rear than older ones with the same or
higher GVW rating. Same with GM 3/4 tons too. To improve ride for
sales they reduced spring capacity resulting in a mushier truck at GVW
with new models than with older ones.

Or he could go with a Freightliner and choose his power as well as having a
better truck than a Ford.