The map is coming along nicely. I'm glad to hear you are close to completion. However, I have a few more things you may need to look at. (I bet you hate me by now. )
The broken button has no visible effect when stood on to show that it is broken, which may confuse people.
If you put the box on the any of the buttons whilst also standing on it, then get off, the button unpresses, even though the box is still on it.
The doors still have a small gap on one side, that can be seen through when closed.
If you stand on the button that makes the steps rise, whilst the glass still exists, it shows the zig-zag effect where the step edges touch the glass. Consider making the glass slightly thinner on the outside.
Inside the room with the rising steps, there is a wall with the nodraw texture, on the face directly above the door.
It is also still possible to get stuck in this room on the opposite side of the glass, unable to activate the steps (although it takes some stupidity to do it). The way I see it, only the bottom half of the room needs to be concrete, which would make it impossible to get in the room until you break the glass.
Other than these few things, the map is looking a lot better now. As for your problem with getting the player into the pipe, try using a func_push pointed upwards, then another pointing into the tube at the top. The upwards func_push will be activated when the player jumps whilst below the pipe. (I like the effect you used there btw
)
You may also need a point_clientcommand to make the player crouch whilst in the vent as well. Use the command "+duck" when entering the tube, and don't forget a "-duck" at the end, so the player isn't stuck permanently crouched afterwards.
*Edit: Corrected commands for crouch.