Congratulations on your new critter. I'm sorry you had a rough start with the mites. I hope that's all sorted out. I've heard really good things about Frontline for mite treatments.
I'm not surprised that your snake is on high alert when you enter his enclosure. He's most likely looking for food. I think twice a week is a little on the heavy side and a 5-7 day feeding interval might be more appropriate.
Hook/tap training is just a light tap/rub on the snakes head or body. It usually shuts off that feeding response and let's the animal know it's about to be handled or you're doing cage maintenance. You can use a snake hook, paper towel roll, wooden dowel, etc. Please share pics of your critter and setup when you can. Best Wishes.