Kurotowa
Legend
I've heard this, too, but I can't recommend Tyranny of Dragons (Hoard of the Dragon Queen and Rise of Tiamat) to someone just getting into the game. It needs a lot of tweaking.
"Needs a lot of tweaking" is exactly the reputation I remembered for those two, that's what I want to avoid. Thank you.
I'd recommend ToA either way as just being a solid adventure top to bottom. I loved it. Furthermore, there's some excellent supplementary material on DMsGuild to really flesh it out.
How much of ToA is in the actual tomb? My group gets bored with dungeon crawls pretty quickly, so I probably don't want to throw the granddaddy of killer dungeons at them.
In general, thank you for the replies. Lost Mines is off the list because, after refreshing my memory, my group already ran it when it and 5e were new. Neither I nor they are new to the game, what's new is me taking a turn in the DM seat. Curse of Strahd is also out for the same reason.
Right now I'm still leaning heavily towards going with Ghosts of Saltmarsh set in Eberron. The fact that it has level gaps is noted, but as people have pointed out there's both Yawning Portal and DM's Guild to help fill those in.