Yes, there are! Just one that I know of. I had to read it for a Stalinist history class.

It's a book called Gulag Boss written by Fyodor Vasilevich Mochulsky.

It's a great read! Hope you enjoy it.

From what I understand (I most recently read Malia's book, Tragedy of the Soviet Union) the Gulag archipelago was incredibly inhospitable, to the point where survival after 3 months wasn't likely

Lets not get too carried away here. The totality of the Gulag was greatly varied - some camps were better than others for treatment/mortality. For example a Sharashka was a much nicer place to be detained than one of the labour camps of 'harsh regime' set up post WWII. Time is also a factor - for example mortality in the labour camps went up during WWII because of food shortages.

the actual prison guards. Where did they live?

The guards and camp administrators would have their own buildings generally. The quality of those structures could vary a bit though. Narratives of the establishment of Nazino Island (later called Cannbial Island...) for example suggest the guards had no more shelter on arrival than the inmates. Fydor Mochulsky, referenced by contomate180, IIRC noted the first sub-camps he arrived at had few/no permanent structures despite their being practically in the artic and winter coming soon.

Did they aid prisoners at any time? Torture them unnecessarily? Both, depending on the guard and context. You might consider a lot of the guards cruel acts could just be plain neglect. I recall Solzhenitsyn repeated a story of prisoners on a train trip to a labour camp being denied water, and Solzhenitsyn suggested this was probably because carrying buckets of water to the prisoner's car was a big chore so the guards didn't bother.

Some guards helped other prisoners for various reasons, such as getting them nicer jobs in the camp. Like an office job is better than breaking rocks in the mines. But sometimes they did this to help out the non-political prisoners too.

What were the benefits keeping them working there, if any? At a guess some of the people working in the camps weren't there by choice anyway - both Mochulsky and Dovlatov (referenced in my other post) essentially got ordered to work there.

You might also consider some of the guards were former prisoners, and they couldn't get a whole lot of other work. Some were reluctant to leave the 'zone' because having been thrown in prison they just couldn't relate to the rest of the world or what they had was lost while in prison (e.g. if your wife leaves you). Many (all?) had a 'wolf ticket' and couldn't travel freely anyway. Also some of the other 'free' camp workers were former inmates who stayed on.

Just to round out the cycle, some of the 'free' camp workers could end up in the camps. Mochulsky relates that the administrators of his camp complex got arrested for their neglect not long after he started up. This sort of links back to some of what I was getting at earlier - back in Moscow they weren't greatly impressed with the inmates dying, but their concern was primarily that the camp system had work targets just like everywhere else and needed to deliver on those, and high mortality wasn't always an excuse.

Anne Applebaum's Gulag: A History is actually a pretty well rounded overview of the gulags once you get past her introduction. She seems to have a chip on her shoulder about 'speaking out' about the Gulags... which has been old hat since for a while now but I digress. Fydor Mochulsky's memoir is also good.

I'm also keen to check out Alan Barenberg's Gulag Town, Company Town as another view of the history of a gulag complex.