I am going to list some things that may seem obvious just to cover all the bases because it's absolutely impossible for me to know what you do and don't already know.
-Some type of enclosure that locks in a way the animal cannot escape
-heat source of some kind that can only get power through your thermostat
-water dish that is really difficult to tip over
-two or more identical hides that are sized where your BP fits quite snugly inside
-humid hide with sphagnum moss
-other "decorations" to cover up most of the area that is not taken up by the hides and water dish *I would avoid hard to clean items like wood for the first 90 days*
-digital hygrometer
-paper towel as substrate for 90 days then usually coco bark or cypress mulch works best unless you live in a humid climate
I would recommend having that all set up far in advance so you can fiddle around with the settings to get it just right before the animal arrives.
-spray bottle to mist (I prefer the big ones meant for garden fertilizer that have the small hose but you can use a normal one)
-paper towels to spot clean
-tongs to offer prey
-appropriate sized f/t prey unless the animal is used to eating live, in which case it may be best to stick with what she is used to for a month or so
-kitchen scale
-small locking tub with a few air holes drilled or a "critter keeper" to keep her in while you are doing full enclosure cleaning
-hand sanitizer to clean your hands and tools (after they touch her or her enclosure or other animals and their enclosures) to prevent spread of disease to/from your other reptiles
-snake hook to break feeding response before handling her (many people don't need this with BP's but if you are apprehensive about taking a bite I'd use one till you have practice how to pick her up)
-make a reptile first aid kit with items like vetricyn, betadine, qtips, popsicle sticks, cotton balls, tweezers, syringes (without the needle), unflavored pedialyte, and contact info for normal and emergency vets that both have a lot of experience with snakes