Of course the SIMPLEST thing is to literally use the Saves and Combat from C&C - transplanted over to AD&D 1st Edition. It works really well, with little or no tweaking.
There are several things you HAVE to do -
The main changes are to remember the AC conversion, and don't forget to add the level/hd/difficulty to the base challenge rating.
(I actually PREFER some of the things they have done with the Character Classes in C&C, Monks are actually tough, Cavaliers have been more correctly called Knights, and Wizards get extra spells for high intelligence - something I've always done in D&D - it just seemed logical).
Keep it fresh with your encounters, but don't be afraid to use old favourites. I've done quite a bit of converting classic monsters to C&C, as WizBro are touchy about the licensing other publishers simply can't use them under the OGL. Something which (if you know the history of some of the monsters) is a complete travesty. Take a look at what I've posted in the past, and use them as GUIDELINES - as Gary Gygax said "The secret we should never let the gamemasters know is that they don't need any rules" - I always have taken that as gospel personally, and NEVER let the rules get in the way of running a good game.
Lastly, always remember even though you might be the "Master of the Game" its your duty to keep your players entertained and happy - and (hopefully) just a little bit worried and scared!