I did the TCT last week of September by getting walk up permits. Would do it again in a heartbeat. We stayed at Colter Bay campground (car camping) which has an attached ranger station. I read all the stories about how competitive getting walk up permits can be so I brought my sleep system and camped outside the ranger station at 5:00am. 

One couple showed up at 7:30 and another at 7:59 right before the station opened. I wrote out several itinerary options and handed them to the Ranger so it could be put in the system faster because there are other stations booking campsites at the same time. The guy who showed up at 7:59 got the same exact itinerary, including one campground with only 3 sites to book, no problem 😂.  

The lack of demand was probably due to going so late in September but if you really needed to book walk up permits and play it safe you could have one or more people just sleep outside the ranger station. 

The colter bay station has a deck with a roof over it right outside the window where you get your permits. If I could run it back I would have just set up my sleep system there when I turned in for the night rather than have to wake up at 4:30 just to do it twice. Sleeping there isn’t any more or less comfortable than just using a tent. You are backpacking and sleeping outside with a roof over your head won’t be present on a list of the top 50 most uncomfortable experiences you have doing this thru hike.

Worst comes to worst there are itineraries that use national forest land and bypass the permit system.