It was fun - the players were a mix of those familiar with the older rules and those who'd only played 5th edition. I like my house rules like anyone else, but for a one-shot (it ended up being a two-shot but was designed as a single session) I thought it would be more fun to keep it as close to what was written in that little booklet as I could.
For ability generation, I had everyone (I had six players) roll 3d6, and we recorded the results. I then rolled 3d6 and replaced the lowest result with what I had rolled. Everyone could then use this array in whatever order they wanted for their characters.
Virtually everyone took the 15, the highest roll at the table, and put it in Constitution, though I did have a player choose Charisma instead. The fact that the prime requisites don't do anything other than adjust the rate of experience gained made it easier for characters to look at using their highest rolls for abilities that give them mechanical benefits such as an extra hit per hit dice, a +1 to ranged attacks, or even a better reaction roll, than for simply making a fighter with a high strength, a wizard with a high intelligence, and so forth. At first level, where everyone had to roll their first hit die, min/maxing consisted of picking Constitution as the best ability.
For equipment, I used the OD&D equipment lists from (now) Necropraxis, which helped speed the character creation process up. I still had a couple of players who wanted to generate their starting gold in the traditional manner and purchase it, but the lists were appreciated by most.
One potential 'house-rule' that I used was in the interpretation of the 'withstands adversity' entry for Constitution. Rather than having a player die when reduced to 0, I allowed anyone to roll a d20 for a 'death save' instead. One of the characters was dropped to 0 as he tried to run past a line of crossbow-armed highwaymen. As a 15 Constitution has the 'withstands adversity' entry, I told the player he only had a 5% chance to actually be dead, and let him choose the number that would represent a failure. Unfortunately for him, he chose 20 and rolled a 20, so his poor magic-user ended up dead. For other another character who had been reduced to 0, they were able to limp along and continue adventuring, with the understanding that they would be killed if they were hit again for damage.
For anyone interested, here is a summary of the rules and interpretations I used:
- The table rolled the stats using 3D6, and were allowed to arrange that array as desired
- The encumbrance and movement rules from Men & Magic were used
- Elves were allowed to start the session as either Magic-User or Fighter (player's choice)
- The Alternate Combat System (the d20 method) was used, with adjustments made for weapon vs armor type (from the Greyhawk supplement)
- No player character or hireling has darkvision, regardless of race. The players were told to presume that every monster, regardless of type, could be presumed to see in the dark
- Players rolled their character's first hit die
- Any character reduced to 0 rolled a 'death save', a % score based on their Constitution
- Turn structure and initiative were used from CHAINMAIL
- Elves were allowed to split move and fire, per CHAINMAIL