How long and how successful the OP will be dropping camping for the first time will be more about the OP's experience and knowledge vs. the weather.
None of us can predict the weather or the temps. None of us know the parasitic draw on the OP's battery.
Wwe all know it can be done successfully however there is a learning curve the OP will have to adapt to
TO the OP you will have to monitor your 12 volt use very closely. I assume you only have 1 battery? You will need to avoid using unnecessary interior light if you do not have LED lighting. Use water pump sparingly.
Consider recharging battery via the truck but that is not a foolproof method.
It can be done, but your first time without a dedicated method to recharge you will very likely run out of power over the course of the long weekend