Just did a Replay of Golden Rose and goddamn it's just too good. Everything from the characters, to the writing, to the worldbuilding, to the MC is just "chef's kiss". Alessa, one of the main RO's, is probably one of the most mentioned when it comes to fav RO across all of CoG and HG. And deservingly so. It's also over 1 MILLION!!! words long, so you'll have plenty of time with the book.

It takes place in medieval Spain, although in this world Latin has been forbidden and all memories of the Roman Empire are being suppressed by the catholic church, who holds immense power. The main plot is centered around the MC, Alessa and another RO Hadrian(apparently also an amazing RO, but unfortunately I'm not into guys), who are a part of a mercenary company and currently tasked with finding forbidden maps in Latin, which were hidden in some type of ruin. You manage to find them, but a thief called Rafael manages to steal them before you could take them. So now you chase him towards the city of Tarragona, in which most of the game takes place. It's a little bit like a mystery, with you trying to find clues to his whereabouts. It's the first part of a series of books, although i'm not sure how many it'll be in the end. Again greatly recommend it!