Death's Ride is one of a few adventures I have had the privilege to both play and to run. While overtly for the D&D Basic rules, Companion set, it can be run (and we did) under AD&D. Though some of the special features were lost I think.
The Barony of Two Lakes Vale gave us ample room to move about and try different things, but the it was the NPCs that captured my attentions the most. Ulslime, Wazor and Korbundar lived on in my games for many more years with both Ulsime and Korbundar even threatening my players in the 3rd Ed. game. One, and I am not sure if he was an NPC in the game or one my DM made up, went on to torture my characters for many more adventures after this.
The Death Portal was an interesting bit of necromantic trickery to get the players something to focus on and the new monsters were a lot of fun (the Death Leech nearly took out my characters back in the 80s.)
Calling it a "High level dungeon crawl" is fair, but it leaves out a lot of what made this particular adventure so much fun.
I still have my original copy of this and it holds up well.