I have some ideas, I hope they help you.

Try some interaction with the "Gun's Elevator Mod", it would be really cool to be able to use an elevator instead of stairs to enter the bunker. But don't forget to put a ladder too, because every place has an emergency staircase;

I don't know how you'll make the garage, if you can make it underground, perfect! If you can't, maybe you can try some interaction with the elevator mod to transport the cars to the underground garage;

Add some air inlets and outlets in different points in the forest above the bunker, this will give a touch of realism;

Make two different versions of the mod, one with furniture and another with nothing or almost no furniture;

It may be necessary to make an enclosed area with metal fences above the bunker (like in the March Ridge bunker), so we can position generators and rain collectors;

Be careful where you put the bunker, try not to put it in the same location where famous map mods have already implemented content, such as "Grapeseed [B42 Unstable Remake]";

Thinking about roleplay, it would be nice to have a longer entrance, a longer corridor. Imagine that you would need a narrowing point to be able to defend the bunker in case of invasion, it makes sense from a realistic point of view;

Take a longer road (not too long) to get to the bunker, after all the idea of ​​a bunker is to be hidden.

My idea was to make the bunker invisible from the outside, hiding a vehicle ramp inside a barn and a staircase inside a shed, like you can see in this video https://youtu.be/zBKO87FbWqI?si=O85HA5UxijqvDj4-
Because of that, I don't like the idea of surrounding the area with a fence, but I'll put an indication of where generators and rain collectors go, of course.
I'd rather avoid using someone else's mod as a requirement for the mod tbh, so I won't add compatibilities with an elevator mod.
I already had in mind the two versions of the mod: One without loot, and one without furniture. I was also thinking about adding a third version that spawns with furniture and loot. Some people seem to want that too and it's not that hard to add once you have everything else working.
About the longer entrance, I was also thinking about connecting the bunker to the house using a tunnel like you can see in the video.

Originally posted by Fred Cooper:

My idea was to make the bunker invisible from the outside, hiding a vehicle ramp inside a barn and a staircase inside a shed, like you can see in this video https://youtu.be/zBKO87FbWqI?si=O85HA5UxijqvDj4-
Because of that, I don't like the idea of surrounding the area with a fence, but I'll put an indication of where generators and rain collectors go, of course.
I'd rather avoid using someone else's mod as a requirement for the mod tbh, so I won't add compatibilities with an elevator mod.
I already had in mind the two versions of the mod: One without loot, and one without furniture. I was also thinking about adding a third version that spawns with furniture and loot. Some people seem to want that too and it's not that hard to add once you have everything else working.
About the longer entrance, I was also thinking about connecting the bunker to the house using a tunnel like you can see in the video.

This is an awesome idea, I like it.
But if you're going to make something as big as the one in this video, can't you make an optional mod that's a little bit smaller? I mean, a slightly smaller bunker, more like your current mod, because this one is huge, and I think other people, like me, would like a smaller option if possible.

That was the idea. The giant one in the video is my personal bunker, made for myself and some friends. The new bunker is going to have the same size as the current one.

I am so excited for this mod update/ new version. everything mentioned above by you and the ideas all sound amazing. I'm so excited. please let me know once it's done