1 or 2.
The first was Shackled City. It was fantastic.
The group splintered on the 2nd to last Age of Worms - almost had finished in the Wormcrawl Fissure adventure. But the players of the Binder & the Cleric moved.
But, I did run a space/time continuum Warp campaign where each player picked 1 path (usually from just the titles or artwork)- & I picked the individual book within the path for them & linked them all together with the final Age of Worms adventure starting the finale, then a reboot finale from Shackled City (there were 2 players who had gone through that the first time there) to end it.
(the paths picked were (in the order I ran them i.e. book 1 to 5 from the listed paths, with my own combined finale : 1. Giantslayer
2. Second Midnight
3. Carrion Crown (I only owned 2 of this path at the time, so not many options. After a few years I still only own 3 of this one)
4. Legacy of Fire
5. Jade Regent (after looking through the players choices & juggling the order I would put them in I felt this one had to be either first or last so this was locked into it's order first)
I look forward to doing another Warped 2 soon - but I do want to run RotR sometime by itself.