Apparently, this puzzle was a real twial for me. We can start with the fact that I entered OLDBAGOFTrIX, clearly missing the twick of the puzzle entirely. And ignoring the fact that it would be a weird bag of Hallowe'en candy that held just loose sugary breakfast cereal.
I couldn't see SLANG, even with SONIA in place. My mind wasn't even convinced that her name wasn't SOfIA for a while. I wanted imho instead of FWIW (29D: Texting equivalent of "This is just my opinion, but ..."), this time ignoring the fact that the word "opinion" is already in the clue, so it wouldn't be in the answer (even abbreviated). I put rATTY in for a while instead of the definite "huh?" of TATTY (41D: Ragged). I wanted "olio" for 9A: Hodgepodge (HASH), and I'm glad I was wrong.
Too twue. Whew!
But all that's okay. Once in a while, it's good and humbling to have a puzzle that WHUPS your behind (relatively speaking).
The theme is fun: take phrases whose last word begins with TR- and treat it as if you were a three-year-old who can't pronounce the letter R. In three of the four examples, the respelling with a W results in a completely different looking word. Thus "trees" becomes FAMILYTWEEZE. Cute. The final answer at 46A: CliffsNotes version of "Huckleberry Finn"? (HIGHSPEEDTWAIN) is so lovely that it doesn't matter that the word didn't change appearance.
MAJORDOMO and FACESWAP are nice answers in the fill, as is the complete SAMSPADE. Tough to have old clunkers like OLLA and STYE in the puzzle. And it probably would have been more elegant to avoid TWIT in the fill. But overall, the theme made the puzzle a definite tweet.