Play the Half Life 2 Campaign on Gmod, with sandbox enabled?

Pretty simple question, looking for a simple answer/solution. Any way me and my friend can go about the entire HL2 campaign while using custom addon weapons and gadgets?

Just load up the Half-Life 2 maps and your friend can connect to your server? Nothing else special to it really.

The HL2 maps can take a really, and I mean REALLY long ass time to load though because of Gmod’s current way of doing it.
So if you’re fine with playing really short maps at first and then having 5-10 minute loading screens then yeah, there you go.

And the fact that HL2’s campaign in GMod is pretty buggy. Man, I remember that rescripting someone did that actually made the HL2 campaign sort of workable. Was a ton of fun with a billion players on.

I recommend synergy.