Basically if you are building a housing block, you need to make sure that your fire, architect, police, bazaars, apothecary, physician, dentist, school, library, taxman, temples & water are the house side of the roadblock. SYs & granaries can be outside as bazaar buyers will cross roadblocks (but not bazaar sellers); booths/pavilions etc can be outside as can the juggler schools etc as the performers will cross road blocks to get to their destinations. I think senet houses have to be inside the road-blocked area, but can't swear to this.
Remember if you have SYs, granaries etc outside your housing's roadblocks, they will need a couple of houses to supply labour + fire, architect, police & apothecary to prevent them disintegrating or the people dying.
Hope this is clear - it's very easy once you get the hang of it, but incredibly difficult to explain! I got through the whole of Caesar 3 without using gatehouses (the game didn't have actual roadblocks) as I thought that it wasn't fair as that wasn't their real purpose ... but they give you roadblocks in Pharaoh, so I use them all the time.