" I am generally more active on holidays too.
Its generally how it works.
I have a fitbit watch and at my last job was l'd regularly hit the 10k steps mark by 2pm, be home by 3 and then kick into feeding the animals and yard work. This current job and living in town I'm lucky to to 5k
a day.
But camping /4WDing with wandering around scrounging/splitting fire wood, clearing or checking sketchy bits of track before driving it, getting out of the car to have a look at the view or even just drawing water from the creek just to get dinner on. Its all incidental exercise that you don't get at home as everything is conveniently located and you don't have to move.
You don't really notice you're doing it, but the constant movement keeps your metabolism ticking over at a higher rate and burning off the kJ. Probably also why I always seem to sleep better when camping.
As long as you don't completely cave in, sit by the fire doing nothing and live on cream dip, corn chips and beer all weekend (don't get me wrong, I'm not opposed to such actions), then I'd say the kJ in and the kJ used would easily balance out.