To clarify:
I'll be developing film and printing. Black and white only. I'm using Kodak D-76 & Dektol as developers and Illford Rapid Fix for fixer... haven't committed to stop bath but leaning toward that orange stuff Kodak makes, (can't remember the name off hand) or maybe just plain water.
I know that I'm not sensitive to those chemicals as I have used them extensively in the lab at the college. I feel like they are pretty innocuous because I did all my developing with bare hands and no tongs.
I don't plan on using the room for more than an hour at a time and will have the chemicals covered during non use and the door open. I can't immagine having more than an hour of time anyway...the three-year-old will be outside knocking as it is.
If at all possible, investigate the installation of a fan that will vent to the outside. Usually any bathroom that doesn't have an overhead vent has a window; those are building specifications. A fan would be the best solution. If it is simply not doable, stick to your rule about not being in there more than an hour at a time, and crack that window (top & bottom) to air it out.
When you say you "will have the chemicals covered during non use and the door open," can you clarify? If you mean keeping the mixed chemistry tightly capped off in appropriate jugs, that's fine. If you mean leaving mixed chemistry in open trays covered with plastic wrap until you get back in there, that's not so fine. Dump your trays when you're done and rinse them thoroughly.
I appreciate Joe's warnings, but also consider that these chemicals have been tested/re-tested, worked with by photographers AND chemists alike, over many, many decades. Clearly ventilation is an important consideration for a darkroom. We also have numerous household detergents, cleaners, and sprays that contain ye olde skull & crossbone warnings on the back about prolonged inhalation but can be handled safely.
Oh, and should you ever get into toning your B&W prints, ventilation becomes even
more important. You must do it in a well-ventilated area or even outside.