Glad you're finding it fun! I had fun, too, but was pretty stressed when I did it. I completed it in 2010, and hs1917 then was a bit different to yours. Nonetheless, I think they're both quite challenging.
The huge amount of work and frustration involved can be demotivating at times, but I think the end result is well worth it.
I understand what you mean with the lab tasks, the difficulty of them as the weeks wear on jumps up. Especially annoying with school as well.
Being a mentor is okay, it means I'm a not-really-tutor since I'm not in university yet. I don't do as much as tutors, but I try to help! It can be rewarding. It can also be frustrating if you don't know how to explain a concept that you understand well. In any case, it's still good fun, especially meeting other people with similar interests.