I just looked up the speed/fuel burn for the 29 with a Volvo D4. Speed at 3000 RPM is 15.5 knots fuel burn 10.2 GPH. That would be about 66 gallons. Fuel capacity is 145 gallons.
From Cape May to Atlantic Highlands would be 6-6.5 hours. I have done this trip many times at 7 knots or less and would have no qualms about doing it in a Ranger 29 especially at 15 knots. Just need a half decent day.
North Pacific 45