For hit points I'm simply sticking to LL for PCs and will adjust any monsters that need to be tweaked on the fly. Generally sticking to the lower power levels.
For saving throws, the Mutants & Mazes section has some decent advice, basically giving equivalents for the save types between systems. Rather than bog the players down with it, I'll just keep these equivalents in mind when asking for them to roll.
Character Saving Throws
Mutant Future **** Labyrinth Lord
Energy Attacks **** Breath Attacks
Poison or Death **** Poison or Death
Stun Attacks **** Petrify or Paralyze
Radiation **** Wands
Spells or Spell-like Devices has no equivalent in MF, so I'll just the PCs'/monsters' LL saves for that.
Make sense? Or am I missing something?