Lost story

[quenchy]

I hope that you will be able to help me as I'm sure that you have read thousands of pages and the chance for someone among you to have came acrosss this story will be great.
When I was a teenager I took a book from the City Library of Sofia. It was an antology with random sci-fi short stories and novels. It was an old, tattered book and it was torn apart, with the last 20 pages of it missing. The last story that was published there grabbed my attention, but I was foolish enough to allow myself to forget the name of the story and its author.
Nearly a decade ago a thought began to haunt me - what is the name of this short story? I sat down and began recollecting about it. But I was unable to find out anything in the web - you know, it usually contains tons of useless information. So now I hope that you will be able to help me find this story. I'll share whatever I can remember:

1. The setting is a post-apocalyptic future
2. The war was waged with exotic and exquisite weapons
3. Survivors are few and possess almost limitless resources and technology
4. Robots tend for the last of the humans
5. Humans don't want to progress anymore because they have witnessed the results of this progress. They live bonvivant lives and care little for the future or the meaning of it.
6. The main character is refered to as a cowboy who lives in his ranch
7. The main character sets on a journey towards a nearby megapolis that is ravaged by the war and filled with horrors
8. The main character receives a gift-guardian, a robotc horse armed with very smart AI and protective and combat equipment
9. The cowboy and the horse pass alongside lakes of molten mercury, and the horse tells the cowboy that in these lakes live metallic gnomes that stalk unwary travellers and catch them, then they begin tossing their victims to one another in a horrid game, eventually tearing the victims apart.
10. The cowboy and the horse have to find an alternative route not to cross a highway, because above the highway angry ethereal entities swoop the sky, waiting for anyone to touch the highway and then they kill them.
11. Inside the dead city the cowboy and the horse have combat encounter with a group of genespliced hyneas with scorpion tails and the ability to mimic human voices. In the Bulgarian translation they were mentioned as "scorpienas"

After this, the pages were missing.

I tried to look up in this magnificent tool of Google, but usually the robotic horse search resulted in some weird cartoon or cybernetic experiment. The cowboy - or post-apocalyptic cowboy - also yielded results from some games such as fallout and rage The scoripenas lead me to some random fantasy monster manuals and stuff. Et cetera.

Then I went back to the Library. It appears that they keep records only for 8 years, so I couldn't find the books I took. I remembered how the book looked like (I have good visual memory) and I began swooping the library for the short story book, but didn't yeild results. I asked the librarian to inform me for any tattered short story book that is returned. This led to four false calls.

Now you are my hope. Please, delve in your memories, ask friends and help me find this short story.

[Neurosis]

Never read it, but it very much sounds like something by Jack Vance.

[quenchy]

Probably it's Vance-inspired, but I've scooped through as much of his works and I'm sure it's not his.

[quenchy]

I've found it! I've got a PM from another forum. The story is written by a Bulgarian author - Krasnomir Karchunov - and it's truly worth the troubles! I'll try to find it in English so that I can share.