Scifi: a portal in the bathroom triggered by the paper towel dispenser leads to a time warped secret society

I think I read two books or short stories. One day she discovers that she has entered another place through the above mentioned portal. Now that she knows about them, she has to stay, but this isnt so bad.

She has a studio above a pub/bar. She frequents it and the barman knows her.

The underground place is run by some scarily efficient people from other times and places. Mayan and Egyptian ancients. Their goal seems to be protecting humanity from itself.

There's a "park" but it's only for daytime use. She sets up a camera and figures out it's not in our solar system.

She meets a guy. Finds out that to conceive they have to live in the "normal world".

main locale remembered is Washington DC

i read this in the last 10 years