Reddit mentions of Ad Alpes: A Tale of Roman Life, 2017 Edition (Latin Edition)

Lingua Latina Per Se Illustrata is great. Read it at once. Answer all the exercises in Latin, if only mentally. Read and reread. You've learned enough about Latin, now it's time to see it in action.

If your library is good with getting suggested purchases, ask for Ad Alpes when you're done with Familia Romana. It is good for continuing to drill the grammar from Familia Romana while broadening your vocabulary without the brutal ramp-up in difficulty of Roma Aeterna.

As for online resources, Dickinson College Commentaries contains ten relatively easy Latin texts with very helpful running notes and vocabulary, with more to come in the future. The Lewis & Short dictionary on Perseus is a useful reference, and the Word Study Tool is very helpful if you ever get stuck parsing a word. Gildersleeve's Latin Grammar and Allen & Greenough are invaluable.

And I have these suggestions for online reading material, roughly ordered from easiest to hardest. To find more free books like these, pay attention to the publishers' advertisements and search Google Books or the Internet Archive.

• Fabulae Faciles by Frank Ritchie — Four very easy retellings of Greek myths, with some sheltering of grammar in the first two.
  
• Eutropius, edited by J. C. Hazzard — Eutropius' history of Rome is remarkably close in style to the literature of the Golden Age, and yet easier to read than any author from that period.
  
• Cornelius Nepos, edited by Thomas Bond Lindsay — The easiest Classical author. His surviving works are a book of Lives of the Outstanding Generals of Foreign Nations, and portions of Kings of Foreign Nations and Roman Historians.
  
• Caesar's Gallic War, edited by Arthur Tappan Walker — Traditionally the first book of real Latin read by students because of its combination of simplicity of style, purity of style, and intrinsic literary interest. The received text of the Gallic War is in eight books, but this edition lacks the eighth because it was not written by Caesar.
  
• Select Orations of Cicero, edited by J. B. Greenough and G. L. Kittredge — Cicero's advice on how to improve your Latin is to read Cicero: orationem autem Latinam efficies profecto legendis nostris pleniorem. "You will assuredly make your command of Latin more complete by means of my writings." "The Citizenship of Archias" is not too difficult.

Perhaps not 'real', but Ad Alpes is a full-length intermediate-level story in excellent Latin. It was written to ease the transition from Caesar to Cicero.