My 10 and 14 year old have spent the last several months discussing a BP as a pet. I figured it would pass so I didn't make an impulse buy and have instead let them spend the last month or two on youtube reading the do's and donts. What it takes to care for one, cost's, etc. After a couple months the thought has not gone away and are saving their own money to purchase everything.

We went to a local reptile show a month ago just so they could hold some and see how they would act around them, I thought the youngest might be scared but he is now even more excited. We spoke with a breeder there and are going to meet with her again at the next show in November, so I want to get a game plan together in the mean time.

We didn't plan on going with a brand new hatchling but we still wanted one young enough, hopefully out of the nippy stage and one that has been eating and getting through sheds OK. Assuming that is what we end up with I am planning to go with a 20 gallon long tank, heat mat, multiple hides, water dish, and probably a CHE as well. I am pretty handy around the shop so my long term plan is to build something similar to a T8 as it begins to outgrow the 20 gallon glass tank. Assuming the kids are still interested and active I would likely go with a heat panel in the permanent enclosure.
I have been watching craigslist so if I come across a deal on some other type of enclosure/terarrium I am not dead set on the 20 gallon long, those just can be gotten relatively cheap new and used.

I have spent the last couple weeks reading on here and my plan is to get things set up in the next month so I have some time to make sure I can keep the temps and humidity where it needs to be. For the basic beginning set up am I missing any necessities?

My list so far:
20 gallon long aquarium with locking screen lid
UTH with thermostat in place
CHE with thermostat in place
2 hides
Water dish
Thermometer/hygrometer (will research brands etc.) for inside
Hand held laser/infrared thermometer.
I plan to use some type of mulch type substrate instead of paper/paper towel etc.
Feeding tongs

The room the snake will be in is upstairs at our house, in the winter we keep the thermostat upstairs around 68 degrees, so I will prepare accordingly to keep the tank temps where they need to be.
If I am missing anything please chime in, I am all ears at this point. I grew up with an older brother who had snakes most of his child hood (mainly boas) so I know some of the basics but am really starting from scratch.