I am ready to upgrade my 1995 Forman but am concerned over the size of the new units. I own a 2001 GMC HD 2500 Crew Cab and want to put the ATV in the box for hauling. I pull a camp trailer and can't leave the tailgate down. Any suggestions on what will fit in the back or how to fit a newer larger ATV?

Get a bigger truck.

Long box won't fit in the garage and ATV are cheaper than trucks....at least for now.

try putting the frot tire on the toolbox or on the roof of ure truck

take the tailgate off and strap the atv toward the cab.

I have the same delema but its actually not a problem. I put my Artic Cat TRV in the short box of my F-350 and also tow a trailer. I use two straps on the tail gate going forward to the front box tie loops and it holds the tail gate against the rear tires at about a 45 degree angle. I've hauled and trailered all over the country doing it this way. No problemo. FYI the two rider TRV is about 8 inches longer then a standard full-size quad. Try it out.

Great advice which I appreciate.
If you place the ATV on top of the box do you use a ramp or will most have the traction to crawl up?

On top of the box? Yes - ramps are required to get up on the tailgate and into the box. Unless your handy at finding a ditch to back into so you can drive it in/out.

Sorry, I wasn't clear with my question. I have a box high aluminum diamond plate tool box that I remove when I haul my Forman (and its heavy and awkward to remove). I'm looking for advise on how to get the new King Quad I am contemplating on top of the tool box once I ride it up my 6' steel ramp into the truck box. I can't envision using my 6' ramp and thought I might have to build some wooden ones...unless there is a simpler way. Perhaps with a locking front differential a quad might crawl up the face of the box but it sounds risky.
BTW, thanks whodatindamud for the suggestion of strapping down the tailgate. Makes sense and sounds simple.

The King will fit if you take the box out.