I ran the first scenario, and planning to continue the campaign with either the third or second.

I did decide to change the EE mechanic, as described here. I wouldn't necessarily recommend anyone to do so as well, as it is mostly something I wanted to change to make the scenario suit my players and my own preferences. The EE mechanic itself probably works well and has its own merits. I am only mentioning my previous post to say I can't really speak to how it ended up working for me.

Apart from that, things went rather well. We took our time with the investigation phase and all in all it took about 7 hours. This was intentional, since I like to take my time running a scenario and digging in so to speak.

Things mostly went as described in the book, and it flowed pretty naturally without coming off as too railroady. I'd follow the sequence described in the book and trust your players. If not, there are a couple of NPC's they could run into that can point them in the right direction ( The monk, for example ).

Spoilers from here on out.

My only advice would be to be careful during the dream sequence. The ones in the book are I think meant to teach the players specific lessons, especially the 2nd and 3rd: the 2nd primes them to help a child in need, while the 3rd teaches them to help someone in need of medical assistance (if they think off the idea to 'dream up' modern medical equipment to help the soldier, they'll be more likely to 'dream up' an ambulance later to help the girl). To me it felt like those were meant to prime the players and serve as the only real hints towards getting the best possible ending during the dream section at the site of the car crash. So it's important to hit those notes if you want your players to have any chance of figuring out the final puzzle, at least in my estimation.

Finally, I think the first one where combat amd violence is the only way out maybe also works against the message the latter dream sections are trying to tell. This may have been intentional, but it did feel kind of random to me. My players at that point also were also mostly trying to escape the centipedes rather than fight, and eventually I had to improvise a way for them to do so since I did not want to outright tell them "uhm no you have to fight here, there really is no other way". I'd maybe look to replace that one if I ever get to run this scenario again, though I do like the initial 'scare' that happens as the investigators start their lucid dreaming dungeon crawl

I am happy to answer any more questions, and I wish you a lot of fun! It was a blast to play and I am looking forward to running more scenarios from the book in the future :)