Your current download is in Apple's ".pages" format, which isn't terribly accessible. I recommend uploading at least a PDF version. If you are uncertain how to do so, please see Apple's own documentation.
I have converted the file to PDF using an online converter, and will be checking it out, but other people may not necessarily go to the effort to cross that barrier. That's why I make the suggestion.
Thanks, I certainly will let you know once I've got it underway.
Found a few more bits and pieces as I've read. (I used to work as an editor, so apologies for the in-depth breakdown here - most of these aren't something that serious, but as long as you're making additions and changes I figure you should be aware.)
First off, is the "Monstrum Monster Maker" you reference accessible anywhere? I haven't been able to find it, either on your itch.io creator's page or via Google.
Next, on page 60, you used "sell their wears" instead of "sell their wares" on first "In The Streets" description block. Second description block also includes "eye them wearily," which may be intended as a play on words from "eye them warily" - but if it's not, it's a homonym error.
Page 63, the Seven of Spades character entry appears to be the only entry which does not bold/italicize a weapon in the passage. It appears there may be a missing separator in the last sentence as well, as the sentence is currently a run-on in addition to the word "swords" not matching the other entries. If I were to rewrite it, I would suggest: "Their giant [bold/italic]shields[bold/italic] are their badge of honor - their [bold/italic]swords[bold/italic], their vow."
Page 64, the Three of Diamonds entry - ordinarily a captain might be described as "reckless" instead of "wreckless," unless this is intended as a play on words. If so, you may want to use further description to clarify.
Page 66, Five of Clubs entry - "Deer" is both the singular and plural for this noun in English, and so "Deers" is incorrect. Additionally, "Chainmail vests" on the Six of Clubs entry is not bolded/italicized as other armors in these entries are.
Page 71, entry 12 on the Table, the stat-block has no condition listed.
Page 74 - This is more of a suggestion than an error, but I struggled to read the font used here. A plain-text version of this letter's contents, set below it, may be of value to others.
Page 75, "The Proving Grounds." I believe you intended to use the word "wary" instead of "weary," but suggest you use the word "aware." The phrasing "make the PCs wary" generally means to make them suspicious or cautious, while this is a tutorial and you are trying to teach the players (which fits the word "aware" better).
Additionally on page 75, this is again more of a suggestion. You mention the Cave Troll in two passages, but don't state its statblock. I would suggest either duplicating the stats here or including a reference to page 70 where those stats can be found.
Page 77, Queen of Spades - the last sentence is missing a comma after the word "Palace."
EDIT- Finished reading the rulebook, final editing notes:
Page 82, Ace of Hearts - the second sentence should not have a comma.
Also page 82, Six of Hearts - the final sentence should not have a comma.
Page 85, "Solforot" section - one of the bullet points is missing a space between the bullet and the text.
Page 102, "Foreign Temple" section - the sentence "Its walls are built from a not found in all Tavolo" is missing a noun, presumably "stone" or "material"?
Page 121, "Health Elixir" entry - "by a master alchemists" has an incorrect article. The phrase needs to either be "a master alchemist" or "the master alchemists."
This is great from what I've read so far, but I figured you should know that you only partly-garbled the LOTR references used on page 41. The starting encounter descriptions use the "parody" name of Helob and reference imps, while the result descriptions use Shelob and reference orcs instead. It doesn't make it impossible to follow, but you may want to revise it for the future.
I really like what you've put together here, and am going to try and run a solo game for myself using this. I'll add on to this comment if I see any other little editing bits you might want to take a look at, and great job!
EDIT- Found another couple spots. Page 49, the descriptive text under "Action Rolls" reads "fast a fluid" instead of "fast and fluid." Also page 52, last portion of the "II. Landmark" section carried from the prior page, uses "Merlin" instead of your chosen rename of "Merlon" - and in the "II. Road" encounter description, you use the phrase "Each player can not roll to loot the Deer" instead of "now."
Just in case you are still maintaining/updating this, it appears that you have accidentally inverted the "Result" table. Based upon your descriptions, a six results in the "Yes, And" answer that the table shows as arising on a one. For anyone who downloads this, just refer to the actual written descriptions instead of the table to avoid confusion.
