Cass rattled in his treble between the 11th and 27th minutes, interrupted by a Tom Jelly strike which made it, briefly, 2-1. Jake Hobbs completed the scoring as early as the 35th minute.
Ramsgate moved up to fourth with two unanswered goals at Merstham. Macauley Murray scored early in the first half, Ian Pulman early in the second.
Folkestone dropped two precious points, and are three away from the play-off spots, with a 1-1 draw at Corinthian-Casuals. Danny Dudley put Casuals ahead on 54 minutes and Frankie Chappell levelled it 12 minutes later.
The draw took Casuals to the 40-point mark now occupied by four teams. That looks like the safety target: the quartet are six points off the bottom and there are five clubs below them.
Two sides who have faded out of the play-off race met at Sittingbourne and the Brickies saw off visiting Burgess Hill 2-1. Pat Harding struck early for the Hillians but Ryan Golding converted a 24th-minute penalty and Jordan Johnson won it six minutes later.
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