Haha, Waxy, I started a map like that a while ago, too. The only problem I found with it was timing all of the func_trains properly. Other than that, it was pretty simple (mind you it's a very small map). Personally, I loved the map, Pulse. You may, or may not, have played it. It featured a system of doors that could be locked, requiring one to take the long way around the map. A lot of people complained, but I found my way through the map my first two or three times playing it, and have known it like the back of my hand ever since. It was a fantastically fun map. It featured outdoors that would hurt players. Humans that spawned outdoors and had to walk to the inside to begin their base, the locking doors that I mentioned, and an array of other gimmicks (cameras, elevators) that added a lot to the gameplay.
TL;DR: While a lot of people will complain about getting lost, if the map is well built, it'll still be awesome fun.