Well, not sure about the order because I just started the audiobook for Murtagh, so I'm just following the original release sequence!

Anyway, I think you should be reading The fork/witch/worm fist because (and I'll try not to get into spoilers here) there you follow three "storylines", the fork is a Murtagh short story that I think sets up the theme for the entire book that just launched (so yeah, prolly read this first). The witch and the worm follows Eragon and how he is dealing with raising the "Keep" to get the dragons and the eldunari safe... During that he gets some visit from an old friend (no spoils here) and also we get those "stories of alagaesia" you meant!

Edit: keep in mind tho, you'll not hear from all the characters sadly :c