How do I make one of those bases with a functional interior?

[bQuest]

If you played the Dunatian all the way back in 1.4 or used any of Juggernoob's habs, you'll know what I'm talking about.

How do I make those ground-bases with an eva walkable interior? I've tried weird complex structures made out of wings and elevons, fairings with parts clipped into the walls (like what they did in the Dunatian.) but I can never get anything to work well enough. What would be the best way to do this? I play in sandbox so I don't have any real cost/weight restrictions.

 

I've provided some of the images I used as reference while trying figure out how to construct this to give you an idea of what I was attempting.

(Image of a dome-esque hab on Duna from u/selfish_meme on Reddit)

(One of the promo images from the Dunatian I found on Imgur.)

(The inside of Juggernoobs "ESA Polar Outpost Nordkapp.." Also sourced from Imgur though this one is downloadable on Steam.)

(One of the shots from SirJodelstein's Dunatian story.. For some reason people tend to plant these bases on Duna and nowhere else.)

 

[Batavia]

You should try using the FreeIVA mod. It works pretty well with bases in my time using it.

Hopefully this helps

 

[magnemoe]

Looks like they build it out of an faring. 
Has seen people build huge ships where it has an interior of structural plates or wings. 
To get in or out its some options., add an hole or have an hatch using robotic parts or an part who open up like the 2.5 meter equipment bay. 
Or you could use an compartment with two hatches enter trough one and exit trough hatch on the other side. 
Never done it myself, probably more practical on an large ship I think