The hardest thing atm most be to restore the SC maps to original HL.
lolz
1. extract original maps from halflife.gcf
2. edit them with ripent to add additional spawns
3. paste to svencoop
4.

5. Profit!
Well you need weapons too, and there is about 90 maps we're talking about.
If you mean to double each weapon on the map, I'd say that would be boring. The Coop run should be well-thought-out and strategic which means you'd have to deal with situations where only one guy can pick up a certain weapon. Then you should make decisions about who is going to get which weapon to achieve the fastest time. (Otherwise just put mp_weaponstay to 1)
However, if you mean to spawn with weapons at the mapstart, you can declare the starting equipment in a .cfg called the same as the map you want to edit, by pasting the weapon names you want to start with.
Example:
weapon_gauss in the c2a5.cfg would mean that you spawn with a gauss in that map.