This is mostly for my own reference, but I thought others might find it useful. There are several supplemental readers available for Lingua Latina, each with a different time it’s supposed to be used in the series. I don’t think I’m allowed to post links yet, but I’ll put in the full names.
To be used with Familia Romana:
Lingua Latina: Colloquia Personarum
Fabellae Latinae (found on Pullins website, free)
To be used just after Familia Romana:
Lingua Latina: Caesaris: Commentarii De Bello Gallico I (partial), IV, V
Amphitryo: Plautus Amphitryo Comoedia
Lingua Latina: Sermones Romani
To be used with Roma Aeterna:
Vergil Aeneid: Books 1 and 4 (P. Vergilii Maronis: Aeneis, Libros I et IV) (Lingua Latina)
Ovid: Ars Amatoria / P. Ovidii Nasonis (Lingua Latina) (for those who have finished the first five caps of RA)
Lingua Latina: Petronius: Cena Trimalchionis (for those who have finished the first half of RA) (note: this book also has a vocabulary guide, be aware of what you are paying for)