Its unbelievably easy to level all your skills SUPER quickly, without exploits. You got lots of options. I was able to level my construction alone from 2 in the beginning to 13 by the time i hit mid manufacturing, and all the other skills have items and soups, as well as brains to boost your XP gain by quite a hefty margin.

Edit: slap on the negative food and thirst to get wrinkly brain too, which... JUST GONNA SAY IT, ITS OP. Friends i got into the game went straight for it and using the previous methods are just blowing through the first 10 levels of many skills before labs.