On The Omnipotent Eye, Andreas Davour has this to say about PHB-only AD&D. That stirred my mind, and this is what I came up with:
Combat:
The weapon tables are in the PHB, as are the HD for the Classes. It would likely look something like Tunnels & Trolls:
Roll your weapon di(c)e and add or subtract any Strength modifiers*, subtract your opponent's value (as above), and then read the AC as follows:
+3 + Fighter Level
+2 + Cleric Level
+1 + Thief Level
+0 + M-U Level
Subtract (Dex-Modified AC#) from 10 and apply the result as HP of damage stopped.
--Thus, AC02 = 08 Hits Protection, AC05 = 05 Hits Protection, AC09 = 01 Hit stopped.
[*] I goofed on the original post. I intended for only the dice of damage roll to be modified and compared.
Saves:
Roll Ability Score or less on d20, reading the governing Ability Score on the Defensive Adjustment modifier, and subtracting it from the d20 roll.
--For example, an Int-based Save with a Int 15 provides an Adjustment of -1 to the d20 Roll.
I suppose one could apply the Combat Bonus above, but only to Saves thought of as Class-favoured Saves.
--I've run my game so long now that I don't think of 'level' as doing a lot of modifying, as opposed to the Character changing over time.
Thoughts?
JB injected some Level-love to the ideas, although there is no mention of the sort in the PHB that I can recall. I've just included it to please the natives. ;)