Hi! I'm kind of new to the forums, althought I've been dwelling around for a long time, I haven't posted anything yet. To sum up, this is my first thread.
I've used the scearch feature but found nothing about this.

This is a part of a world i'm working on. Of course, this is just the early stages so it's super incomplete.



As you can see, I've already done routing paint. But I've come across the following problem:
I want the terraces (the different "steps" in the mountain) to be connected through stairs (so obviously cars wouldn't be able to go from one level to the other, but that wouldn't be a problem since I don't intend to use roads, only sidewalks).
Since there are no stairs availible in CAW, I've came with this workaround:



Place lots like that in the edges, make the terrain routable, and placing stairs there, like this (haven't placed the stairs yet):



But my question is, will NPCs get stuck because they won't be able to simply "walk" from level to level? I mean, can I use these lots as a "bridge" between level to level? Will this cause in-game insane lag? Does it need to be sidewalk connection all over the town for sims not to get stuck? Or is there a way to do something like this involving no sidewalks that doesn't cause sims to get stuck and lagging?

I've also thought of simply modding the stairs with S3PE to make them availible in CAW. Does anyone know if placing the stairs in CAW will be as easy as inside a lot in EiG? And if this will, again, cause lag because there's no sidewalk for sims to walk directly through? Any help is appreciated.

Thanks in advance. ^^

Update
Alright, since nobody answered, I decided to try by myself on a very small scale. Just did a couple of residential lots and made sims to invite eachother over (from one level to another) and they seemed to have had no problems getting there. I assume it would work just as fine if they wanted to get to a different level by themselves.
Here's what the stairs looked like:



Of course, stairs like that are extremely impractical, that's something I'm gonna be working on, but this was just a prototype test.
I assume the main problem of this would be obviously longer travel times since walking down the stairs takes a significant amount of time. But other than that, seems like sims will not get stuck. I'll keep updating the more I experiment with this.

I've tried this in a few different worlds. Once I started testing the completed world in game, I found there were tons of routing fails and stuck sims. Most of the times the sims would not route through one lot to reach another lot. I ended up having to re-invision the look I wanted so the routing was good. It seems to me I saw a texture in a world that looked like stairs from a straight on angle. I think it was Nilxis' Barcelona world. That was just my experience so if you can get it to work, kudos.

I did this one in one of my worlds, but between shorter levels. You can just see the staircase lot on the island with the hospital / science center here: http://www.modthesims.info/download.php?t=538514. As long as the lot was an adequate size and the top and bottom flat, you could try it and see. (I'm thinking of one straight staircase rather than multiple levels.) It would probably be best to put the sidewalk right next to the edge of the lot at the top of the stairs. Sometimes, but not very often, a sim will run up the hill beside the stairs in Bleake Islands. I don't know what effect a whole bunch of staircase lots might have. Good luck with your project!

Thank you for the answers! I'll do a couple of modifications, so there will be a mix of stairs lots and sidewalks going from one level to the other.