There's plenty of porn videos around this (I think because it's an easy premise for being incest-adjacent without - at least most of the time - crossing the line) but I've only ever read the Forget Harper Valley series as a fictional work.
For some reason it's exciting to imagine dads (and moms too) getting together to exchange kids as sexual partners, as ludicrous as the premise is.
Regarding your last paragraph. Melissa's Secrets by Pookie definitely fits neatly into that category. It's a long story but definitely worth it. It gets to what you're looking for a few chapters in.
Only problem with Melissa's Secrets is that its incomplete and abandoned. Some chapters were updated a few years ago but the author has since disappeared.
However, it's not like any major twists or radical new revelations are expected. I would say all it miss is the one final orgy. And what should happen in it is quite clear. At least I had no problem to "reconstruct" the missing ending.
Kelly85 has a number of stories in which her dad uses her to promote his business or to trade for access to younger girls.
It seems that Kelly85 deleted all her/his stories on here.
You can get the original ASSTR versions (lots of underage sex not allowed here) on the wayback machine.
Found a smaller story of a dad daughter-swapping with another dad on a cruise. Pretty fun
A Cruise With my Daughter
IronBuddah has a short series of daughter-swap stories. Currently the second story is in progress:
https://storiesonline.net/series/1762/daughter-swap-stories
Also, Art Martin had a couple, notable "Bartering for the Rent" and "The Swap". Both involve single dads whose 18-20 year old daughters are working sex industry jobs deciding that the girls no longer get a free ride. The girls swap to pay the bills.
The problem is that Martin's site Salacious Tales was on ASSTR, so you'll likely need to use Wayback Machine or similar to find them.
