This drags.
I actually don't mind how silly the premise to 'Gus' is, yet even so it's such a slow and predictable watch. There's a few decent gags spread across the 96 minute run time, but there's so much plainness with everything else. The plot itself is something that feels seen before, across Disney's many high school/sport comedies from these early decades.
As for the cast, Ed Asner is the best performer as Hank Cooper. Don Knotts (Venner) and Tim Conway (Crankcase) are in a film again, following on from 'The Apple Dumpling Gang'; though they aren't a pair here, Tom Bosley (Spinner) teams up with Conway instead. Regardless, none of the three are all that amusing. There are a few other OK but forgettable roles, while the sports commentator bits are way more annoying than they are funny.
Not a production I would recommend, even if you could pick many worse live-action films from this studio to watch.