I've been tinkering around with making a 5E conversion of the AD&D module U1: The Sinister Secret of Saltmarsh. So far, I have finished Part 1 which involves the 'haunted' mansion. I had to take some liberties and make changes to the amount of treasure and magic items found. In the original module, it's possible to find TWO +1 Rings of Protection, so I switched out the second one for a Ring of Swimming instead. This should come in handy in Part 2 of the module and later in the module series U2: Danger at Dunwater. It is possible to find two spellbooks, and some spells in the original module don't have a 5E equivalent, such as 'Fools Gold' and 'Detect Illusion', so I just replaced them with different spells.
My conversion document is kind of bare-bones and still requires ownership of the original module to read the boxed text and other information. But anything that requires 5E mechanics is placed in the Room Key.
Since Rot Grubs make an appearance in the module, this allowed me to use my 5E Rot Grub write-up I did not too long ago. I failed to mention in that post how many rounds it takes for Rot Grubs to burrow to the heart, I decided on 1d4 rounds.
By my calculations, if a standard party of four manages to survive and clear out the mansion and find every piece of treasure, they stand to gain around 824 gold pieces each and will reach 2nd level with around 475xp. The gold still seems high for 2nd level characters, so I might tweak that some more.
Potential magic items are: +1 Ring of Protection, Ring of Swimming, +1 Plate Armor, Potion of Lesser Restoration, Clerical Scroll of Hold Person, 3 Healing Potions, 1 Potion of Speed, one cursed magic item (Cursed Luckstone), two spellbooks.
I wrote up the 5E version of the NPC statblocks for Ned Shakeshaft and Sanbalet. I included the write-up for the Rot Grub Hazard and the Cursed Luckstone in my document. When I am finished, I will post up a link to it.