If there is enough space in the inner, light-tight area to put up a separate shelf for the enlarger then this would allow you to create a wet/dry separation in that space, and save you trouble of having to light-proof the other area and put a second safelight there. You could still use the tub for print washing (assuming it is in the non-light proof area) since this is done in the light. However I don't know whether this scheme is practical given your space.
Originally Posted by zackesch
If you are able to paint your bathroom, then you may find that matt black paint on the door jamb and the area of the door that is in contact with it will remove any residual light creeping into the darkroom. Try turning off the lights and sitting there for 5 minutes to allow your eyes to adjust and then see whether you can see any leaks. I found some around my door (despite also using draught exluders to fill the gap between the door and floor/wall) so I painted the mating surfaces with black PVA and now I can't see anything at all.
I use a red safelight bulb. However when I tested it I found slight but noticable paper exposure at around 60 seconds exposure to the light. Rather than change the safelight, I put a black material shroud around my enlargers that prevents the safelight from shining directly on the paper, and also serves to soak up any light spill from the enlarger. My trays are under the safelight, so I simply put the paper in the developer upside down to prevent any fogging.
A timer is useful but not essential. I started out with just an analog clock on the wall that makes an audible tick every second. I counted the ticks to get the correct exposure, which for my setup is typically in the 15s to 1 minute region (at f/11). I've since been given a timer by a camera club member who doesn't use it any more, and it does simplify life as it allows one to dodge or burn without worrying about having to turn the enlarger off at the right moment. But it's certainly possible to manage without one.