If I find the time this weekend, I'll answer.

I belive I did it with a San Andreas map editor (MEd) and some sort of .dff exporter with blender. I copied models coordinates from MEd and placed them in blender. Then I exported models into hammer editor and made a collision brushes in there. It's obviously a long story short but this is somewhat how I did this.

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2818850947 Doesn't feature any furniture, but hope suit your needs fine enough

this map Is good as a big mac

Good

"ALL UNITS ROCK & ROLL!"

10 year old me shitting myself while visiting this motel in gta san andreas

Oh well, hopefully at some point in the future we'll get em, if not though it's cool

(I've Accidentally deleted a creeperpikmin3 message, but if you see this creeperpikmin3, there is an answer) I wish to see these things as well in gmod, but i'm not currently interested.

Maybe try porting Liberty City? (it can be the one from San Andreas or GTA 3/LCS Portland)

Surprised I didn't discover this earlier. Noice.

YEEE BOOOOOOOY

@UPDATE The first update was just released, rooms from 1 to 4 were added. I'll appreciate any problem report from you.

Yeah, that's cool idea , but motel by itself is empty (besides of "Reuniting the Families" mission or pedestrians spawn bug). Also there would be people which would like to make posing
or scenes, or other stuff and npcs would disturb them

looks great!

will you do the mansion one in SA when you finish this?

Now this is very cool, hope it gets finished.