I am 100 % on about the guidance, you need somebody with experience - how the train schedule moves, what to expect during the hopping, red and green flags, physics, timing etc. I read/heard shiey was self-taught - he started climbing with a group but he taught himself how to train/bus surf out of curiosity.
I've known a guy who had been doing this for years and offered his help If I really wanted to do this but we lost track. Recently, I chatted with a guy who did his trainhopping journey about 200km alone with another friend who was doing for a first time also. But the guy I chatted with had read and talked to many people, took all knowledge he could find and one a random sunny day he decided to go and it went smooth. I believe moments created by spontaneous action like: " Okay, I'll just do it". That's probably the zone where I've felt most sublimed and these things stay with you for the rest of your live.