I use the jumbo Reptile Basic hides for Caesar who is 8+ feet and also for Rosey who is 7 feet and Vicky who is 6 feet. For water bowls, i just use the dog dishes from Tractor Supply. They are like 5 qts or something.
As for cages, the biggest you can afford and place is what you want to shoot for. You can never go too big. I personally wouldnt go smaller than a 6 foot cage for an adult boa but that is just me. There are many people who have kept adult boas in 4 foot cages.