Depends on many things.
The status of your tow vehicle battery
and alternator. If your alternator must charge your tow vehicle battery
then less power is available to charge the camper battery. It will charge both at the same time and take longer.
The status of your camper battery.
The size of the HOT wire that supplies the voltage from your tow vehicle to the camper. The larger gauge of wire works better than a smaller gauge of wire.
Will you be driving at night? Your alternator will have to power the lights
thus supplying less power to the batteries. Remember, it must charge both the tow vehicle and camper batteries at the same time.
How fast you drive. If it takes several hours to go the 75 miles then both batteries more than likely will be charged however if do it in 75 minutes, that may not be enough time.
The best thing to do is to charge your camper battery before the trip/