Dark City Games has a range of solo adventures under their Ancient World brand that is meant for TFT -
http://www.darkcitygames.com/
Same size as the Microgames and comes with Maps and Counters..
BEGINNER: 32 point characters (Free)
The Sorcerer's Manor
Orcs of the High Mountains
NOVICE: 32-34 point characters (Recommend only 1 per party)
The Oracle's Breath
Raid on Cygnosa
Upon the Wind
Ebon Rebirth
Punisher's Keep
INTERMEDIATE: 34-36 point characters (Recommend 2-3 per party)
Island of Lost Spells
Wolves on The Rhine
The Crown of Kings
Sewers of Redpoint
The Thing in The Lake
ADVANCED: 37-38 point characters
Fire in the Streets
Gates to The Underworld
The Dark Vale
Shadows in The Dark
VETERAN: 38+ point characters
Emerald Twilight