I've said a ton of times to so many people...
If you want a good server there are NO shortcuts. You need to have proper coding knowledge YOURSELF in order to create a proper private server.
That being said you have a few options...
Option 1: Create your own source
Pros: You know where everything in your source is and understand it meaning as problems come up or you want to change things you know how. You can chose any patch or edits you like.
Cons: You have to code everything yourself or use other sources as reference... as such it's VERY time consuming
Option 2: use a PROPER source
Pros: There are a couple good sources released. Take one and use it as a base to code your own features. Good sources are.... Hybrids new source (5135) Hybrid's old base source (5017), hybrids upgraded source (5018++), Impulses base source (5165) or immune's base source (5180).
Cons: These sources (except for hybrids new source) contain few if any features. You will have all your base coded (and done properly) but you will not have the advantage of having written the source meaning upgrading things can be complicated as you need to find where everything is and understand how the base is coded.
Option 3: use a shitty source and fix it
Pros: Many features will be coded already (elite coemu or new lotf (eewe))
Cons: The source will SUCK and you will need to re-code almost every single base game feature from scratch in order to make it worth using... if you want something 'playable' fast then this is your option but you should NOT expect to EVER get a proper, stable server as a result from your work on one of these sources... you really would be far better taking your time to learn enough to code your own source instead rather than wasting your time but if all you want is a fun server for you and a couple friends this could work.