Now I don't know if the ignition key switch on the CF Moto cuts power to the headlights when the starter engages or not. If not (and I'm pretty sure the CF Moto doesn't switch off headlights while the motor cranks) then watch the headlights when you hit the key start. If they go way dim then it's almost certainly a depleted battery. If they go right out (and not because of the switch) then it's likely a bad connection on the big wires. That's usually accompanied by a 'snap' sound. the tick tick sound is most likely a relay and as said, means a depleted or bad battery.
Check the voltage. A good place is the big connection by the battery box high in the front part of the left rear wheel well. There and a good ground, a voltmeter should read 12.65 just sitting there no load. Anything down by 12 volts is not good. Less is worse yet.
Sounds like you drove a tow vehicle all day after charging the SXS's battery and when you got where you were going the battery was too depleted to start the machine. That suggests either something was left on that sucked the battery down, or the battery is so damaged that it won't keep a charge.
So why did you need to charge the battery before leaving on the trip? Did the SXS already have known charging or starting issues?
What kind of charger did you use? A car type charger, esp one of the old style that are just a big transformer and a rectifier, are made for the expected load of a car and truck battery and will cook a smaller battery. It would start just fine right off the charger but then would not be able to retain a charge. Just saying...