I've ran Chateau D'Amberville in 5e by converting it myself (mostly on the fly), and it runs pretty well.
The only real surprise was that the guardians of the tomb at the end were ... not nearly as difficult as they were in 1e, because of the whole 5e "solo monsters die quickly" thing.
Do you know what are the specific 5e characteristics that lead to this happening? I was thinking if it is related to bounded accuracy leading to heroes hitting enemies too frequently when compared to the older editions, but on the other hand, every monster has way more HD/HPs now. Then I thought maybe the percentile spell resistance, combined with overall improved saves for high HD monsters was a more effective defense, but then again low level "bosses" usually could not count on those, and it seems to me hyperboosting your melee allies was quite reliable at the higher levels when it finally was not a clever idea to just try to affect a 80% SR elder dragon or true demon directly.
Maybe the poor thief was too ineffective on those kinds of fights (while in 5e they can hit hard in pretty much any encounter) and the cleric was pushed to a defensive game, so the overall offensive power of a "standard four-heroes group" was lower, making fights last longer?
.....
Anyhow, back to the topic, one thing I find interesting in 5e, and that would get lost when playing AD&D is the way saves (don't) evolve. To me it feels low level magic in 5e is generally unreliable (for spells whose effects depend heavily on failed saves, that is. Attacking spells seem less finicky, damaging dex-save spells still get the work done, and some other low level spells even outright just work). This changes gradually throughout the game, so that at the higher levels of gameplay they become very reliable as long as the spellcaster is smart enough to evaluate their enemies and exploit their weaknesses (as even the highest CR monsters still have one or another untrained save, based on a not-so-stupidly-high attribute, which is usually inferable through the monsters characteristics).
The above-mentioned, and also the way attacks in general evolve in relation to defenses, effectively changes low-level and high-level gameplay, and to me it seems that while a low level hero needs to rely o luck and being generally careful, a high level hero is more responsible for their own fate, as their decisions result in more strongly determined results, and this feels right to me.
The added feature of the current save system is that a high level wizard does get a better chance of charming that lowly goblin, something generally absent during the 1e/2e era. Oh, I just realized by writing this that the to say spells do not automatically scale in 5e is somewhat superficial, as whereas damaging spells do not automatically scale damage (as they used to), all spells that are resistible by saves do scale in 5e at least in efficiency.
As a last note, I do feel, though, that some higher-tier monsters in 5e should have some other spell protection buffer, as I am not a big fan of spell resistance giving advantage to saves or of legendary resistances as they are, and am not convinced that either of these mechanics delivers what they wanted to. I did not like the old percentile spell resistance either, as sometimes it would feel like a very blunt solution, but at least it had the work done.