I had solved it 16 years ago after a long - very long - work. One bad thing: I couldn't remember the route. One good thing: I seem to recall, vaguely, one key point to solve it. First, I was rapidly back 2 off on an optimized route. Then I was back 2 off on a different - also optimized - route. That's how I understood that what I seem to recall must be true, so I started working on an entirely different 3rd route, according to my nebulous souvenir. At first I was far away, until I notice a different way to go at a certain location that suddenly brought me 6 off. From there, it was optimization work until I got it.
Soooooo happy!
*Bouncing around my chair*
This level is so incredibly good with all the different difficult routes leading 2 off, and additional difficulty to determine what one is the one... That's 6 stars for me.
Insights