Tomb of the serpent kings one shot?

I was all set to run the next instalment in the Nightwell Barony 5e game tonight, however one of my players had an awfully hectic day and needed a night off.  The other player did show up! So I decided to go totally old school on him and run a game off the cuff.  I had briefly scanned Tomb Of The Serpent Kings (enough to have a gist of level 1 and 2).   So I decided we would give it a go.  I had my player roll up one PC using Whitebox FMAG  and we were off and running with NO PREP. 

When we talked about rolling up a PC he said "4d6 drop the lowest?" and I said "nope 3d6 in order!"  which was a good laugh, but I think he knew what he was getting himself into.  

I gotta say this adventure is well written and there wasn't a helluva a lot of DM loading (ie me reading while the player waited).  I did do a few dumb things, but managed to retcon stuff afterwards.  The clay statues I stated they were outside of the coffins.  

After his first PC and hireling death, he started to get a bit more cautious.  We rolled up Julien Jr (the first PC was a warrior named julien, JR was basically the same guy) and a backup thief and hireling and kept going.  He managed to get to the second level, being even more cautious.  

This time though, he managed to get completely wacked by a lighting bolt, and after being reduced to 0, he rolled a saving throw and ended up with one hit point.  He woke up an hour later and that's where we called the session. 

I'd say playing this module with whitebox is pretty deadly, so I'd trim down a few damage rolls here and there.  The lighting bolt did 4d6 damage, and on a failed save half.  That's still a fryable 1st level character no matter what the roll.  And honestly no matter what the OSR system.  Mechanically I rolled 16 HPs of damage, and said that all the PCs (3) took the brunt of the damage.  He could choose who lost what.  He wound up have 15 HPs total for all the PCs.  So 2 died and one I decided to give him some grace and roll a death saving throw.  On a fail, death, one a success he got 1 HP.  I know it was a bit cooking the books.... oh well. This allowed for a continuation.  

It was super fun. 

After the game we talked about Old school DND and he said that he liked it well enough, but preferred 5e.  Which is fine.  I figured it was worth a taste.  I still would like to run a "open table" game at some point with a large dungeon.  For me settling into DM with no prep on an adventure that i've only ever skimmed was super easy.  Partially because the adventure is very well written and laid out well.  (kudos to the design on that) and also because the combo of a super rules light game like whitebox and the fact that old school is my home made it easy.

Sorry for the rambling. 

The only other executive decision I made was that the Tomb was located in the Nightwell barony.  I want to continue to run games there, and continue to build upon that small map I created.  Slowly develop it.   Everytime I write a "campaign setting" it gets boring and old super quick.  I've realized that is because I'm not playing in it.  I'm not immersed in it.  

Here's a few examples of things that I didn't preplan, but have come up in play in the barony: 

1.  There are dinosaurs, but they are extremely rare.  So much so that if you spot one and can bring it back alive to a scholar you will be paid handsomely. 

2.  I didn't name any of the demigods.  In a previous session they found a shrine to the demigods (actually a meeting place for the demi gods themselves).  I had one of the players come up with a name and he said "Brundle Fly" which is based on the character in the movie the Fly.  Our A.D.D. lead to discussing the fly during the adventure.  Brudle Fly (demi god) God of Nature, Good Aligned. 

Here's the players guide (living document) for the nightwell barony.  I should probably create a wiki.  However it's a pain in the wazoo to download and edit it if I ever wanted to put it in print.  copying and pasting never works well from website. 

https://docs.google.com/document/d/1aD5Cc4-oFUZTLiD6YoGYnis1fVOotXSs21XOnRqqpD4/edit?usp=sharing

Unfortunately I wasn't able to use the sidetrek dungeon tonight, but hopefully the next game I'll be able to.