So... I want to start reading Sword Art Online light novels, but I want to read them from the point the anime left off (that is, Sword Art Online II, episode 24). Does it even go chronologically? How do I go about it?
The two seasons cover pretty much the whole story of the first eight light novels.
Only exception is "The First Day" chapter of the eighth novel.
However as Euphoric wrote the anime does not contain every bit of the novels.
Some things have been left out.
For example the second "Fairy Dance" novel includes an excursion of Kirito and Leafa into Jötunheimr which was left out of the anime.
So much regarding the anime.
The light novels are for the most part chronologically sorted.
The only exceptions are the second (which contains side stories for the first one) and the eighth one (which contains other side stories in SAO/ALO).
So you could start reading beginning with the first light novel or if you want a complete new story arc the ninth one.
There is also the "Sword Art Online: Progressive" light novel series which is a reboot of the original Aincrad arc and contains mostly new content.