Good idea to have a safe room. I personally thought that TBD was pretty much a fast blow through on the topic. My two cents are to take a look at several other products/options for hardening...
For windows (especially like the large patio window in TBD but also a safe room window) you can apply a number of films on the market. They do make it quite difficult to penetrate the window. Enough to seriously slow down or discourage a BG. One is the 3M product....
http://tinyurl.com/yqumbfFor doors you can screw a 3/4" plywood panel to the back side of the door. Use as many screws as you like (10 per side) to bond it to the door panel. Cheap and effective.
Also while using long screws for the hinges and lock is better than nothing please note. If you put a 3 inch screw thru less than 2 inches of wood the extra length means nothing. I would recommend working up the door frame with a product like the following:
http://www.djarmor.com/Home-PageIf you are dealing with new construction or you just want to beef up a barrier on either side of the door for protection against the BG firing indescriminantly into the room you can check out these various bullet resistant panels (cost less than a grand)..spectra shield or armorcore...
http://www.armorcore.com/index-press-chicken.htmlFinally as you do research you will see that there are lots of solutions out there. One interesting one is a pepper spray OUTSIDE your safe room. Easily deployed and a different way to McGiver the problem....
https://www.stopthecrime.com/default.htmIf you get a chance look out for the tv show on Discovery channel called "It takes a thief". Two ex cons spend an hour going over a home breaking into it, then correcting all the weaknesses. Great show to watch.
http://dsc.discovery.com/fansites/ittakesathief/ittakesathief.htmlThe sum is that we will spend two grand on a gun safe and have 10 grand of guns inside it, but aren't willing to spend even a token of that to protect ourselves and family.