Many of us have Class C's that drive/handle/track well, just as they were built/delivered. Others don't. Sometimes there's a pattern but in other cases one owner's coach drives well and another's identical one doesn't.
As a design, Ford E-Series has more of these issues than the GM/Chevy/Workhorse. General consensus is the OEM sway bars from Ford are marginal at best. Sometimes the completed coach gets an alignment and sometimes not. We've found here (thanks, Harvard) that Caster angle isn't adequate at factory settings. All this can be corrected.
What can't be corrected relates to your remark about overhang. If the wheelbase isn't adequate, then aftermarket fixes won't fully solve handling and weight distribution issues. Get the Winnie brochure. Divide Wheelbase by Length in Inches. If it's not in the upper-50's percentage range, good chance it'll have poor handling. In your test drive, go to a truck stop and weigh the coach on their CAT scale. Make sure rear axle has capacity beyond its loading, and the front is at least 1/3 of total weight, or 78% of its rating. If the wheelbase/weight distribution aren't right it's all but impossible to correct.
While you're at the truck stop, make sure the front tires aren't over-inflated (look up a load/pressure chart like Michelin RV has) and the rear tires are equally inflated. THEN take an interpret your test drive.