Absolutely you can run off of battery when traveling. According to Jayco, the fridge uses 640-1200 BTU's / hour (lets use 1200 in the calculation). Each gallon of propane produces 91,500 BTU.
91,500/1200 = 76 1/4 hours for each gallon of propane.
Each standard propane tank is 4.77 gallons. If you are just running the fridge, you should be able to run it off of one full tank of propane for approx. 363 hours.
2013 Jayco Sport