[JRTJH]

Fifth wheel toyhaulers are not "critical" to balance. There's enough pin weight that with the rear garage loaded or unloaded, there's sufficient pin weight to tow safely.

The same is not always true with conventional trailer toyhaulers. We have some members (5 or 6 years ago) with previous "technology toy haulers" who actually could not load their garage without "unloading the tongue weight". A couple of them actually had to resort to loading sand bags under the front bed storage space just to increase the tongue weight enough to get it back up to 9 or 10 % of the trailer weight.

The same holds true for trailers with a "front garage" that's in the bunk room. Loading 1000 pounds of motorcycles or a ATV and a dirt bike in the front will "load up the tongue weight by almost the total cargo weight. Frightening stuff if you're not expecting it...

Those floorplans, I'd guess, were a modification of an existing trailer floorplan with no consideration of axle position on the frame build. Keystone usually designs a floorplan or a series of floorplans that use one "standardized chassis model" and, if anything, they "cut off 3 or 5 or 7 feet of the rear chassis rail for trailers "in that series"...

My guess would be that years ago, when toyhaulers were first becomming popular, Keystone engineered a trailer using an existing chassis, didn't move the axle position, realized after several of those models got into the field, that there's "more to trailer cargo positioning" than they initially suspected...

Today's tongue type toy haulers are not nearly as "sensitive to weight placement" as earlier models, and fifth wheel toy haulers are long enough with sufficient pin weight compared to trailer mass, that loading the garage doesn't affect towability nearly as much as it once did in travel trailer type toyhaulers....

I'd suspect that there are some "ultra-lite toyhaulers" that do still have dramatic differences in weight distribution adjustments based on towing with the toys or towing without the toys.