This guide is obsolete and outdated!
All files you need to play our HL2RP are listed on the downloads page (http://www.catalyst-gaming.net/index.php?page=downloads). Just scroll down to Half-Life 2 Roleplay.
Abbott's Guide to installing content for HL2RP
Pretty simple guide, all you need are these 3 things:
Clockwork Content (http://steamcommunity.com/sharedfiles/filedetails/?id=108727894)
Metropolice V5 (http://steamcommunity.com/sharedfiles/filedetails/?id=104491619)
rp_city45_catalyst_v1f addon (https://www.cubby.com/p/_ae112f3e9b024a1eb463b076f47f1827/CG#Catalyst%20Gaming)
The first two are workshop addons so they will automatically download when you start Garry's Mod.
The addon for the map needs to go in garrysmod/garrysmod/addons as the screenshots show:
(http://gyazo.com/9192c2a394752656cf39b20ccd800ccd.png?1357518694)
(http://gyazo.com/97e7b34b27ff51e4005decc66a2564aa.png?1357518729)
Then you are all set for HL2RP.
The End.
Fixed links -Abbott