I'm not sure but there might be a website that has those campaign maps. You can try downloading the Coop campaign mod though, but some triggers are changed.
or just use other custom campaigns as reference.
The one that is the Starcraft brood war coop campaign mod is just 2 player maps with script Ai changed to the custom campaign for a bit of more difficulty, there is no real changes other then that.
Some maps where focused more, while other were mostly left alone.
For installation maps they use a 50/50 trigger, to equalizing the units for each player, but again no real difference.
if you need to get in contact with them, I do know one of the authors and can get you in contact with them.
I am working on a COOP map of my own that still has the original scripts in place while updating the whole map.
Pr0nogo had a vanilla COOP map that is great if you looking on how the scripts were used.
Sie_Sayoka had the best info anyone can give in his last post, while CecilSunkure nailed it on the head of what most people just use.
I have personally found that Easy/medium/Difficult doesn't react as fast enough for me, while Insane ai kinda over builds if your looking for campaign based maps, which can be good for an expert player.
Pr0nogo has shown how the ai can be difficult when its all working together in a map. (the size, the layout, the proper script, all of that working together to make a real challenge)
If your ever looking for standard melee, just use custom AI (default melee ai) and use insane if you want a real challenge. For Campaign/Co-op maps the level of detail, size and what not (like Pr0nogo explain is how you can really take full use of the Easy/Medium/Difficult AI. The rest are former scripts uses specifically for each mission of the Official campaigns.
I would imagine, use of them would only benefit if you could mimic the mission into your campaign.