It's nice to have something so immersive that you lose yourself and have no concept of the passage of time. That can literally rejuvenate your soul. I took a look at the crawler crane and see now why your nephew will choose another kit for you to work on together. It is very advance.

I have no doubt that you'll be able to teach him as much about the outdoors as you will with the Lego. He may teach you something about mountain bike racing in return lol. It's a win-win!