Great questions!
Drugs
Spaced out and on something...I'd say a natural high!
Drugs are not used. Anything which alters the mind is seen as a deterrent from being able to meditate.
I know some drugs 'open the mind up', but we're trying to go after a natural connection with the divine, which might take longer but you're not dependent on a substance to get you there.
Of course if someone is already addicted to drugs they're not turned away. They can still meditate, read scripture and adopt practices slowly, and over time their addiction may subside or they may find greater strength to get help for it. Many do 12 step programmes alongside their practice.
Hierarchy
We all see (try to see) ourselves as servants of God and of humanity so there is no hierarchy. We call ourselves Das or Dasi (servant) and everyone else Prabhu (God).
That said, there is a certain etiquette followed which may look like hierarchy. For example, the person giving class is respected and we may bow to them (mainly for ourselves, in gratitude). People who have given their lives to the mission likewise. Meals are served to the elderly first.
There is leadership, in that there is a Temple president, but again they would think of themselves as serving their congregation, but some structure is needed to be able to make decisions etc.
Schools
There are Hare Krishna schools in the UK and across the world. I only know about the ones in the UK in detail so what follows is about them only.
They follow the national curriculum so in many ways are like every other school, with a few differences:
In the morning there is an assembly where the whole school gathers to worship together. Very similar to the assemblies I had in school where we sang hymns together, but by my last few years of school hymns had been banned in non-faith schools.
There are yoga classes (although these are offered in a lot of secular schools too).
There is an emphasis on balancing mind, body and soul eg not studying to the detriment of your health, keeping a positive mindset if you success or fail, etc.
There are PSHE lessons which focus on world faith, with an emphasis on Hinduism, and a highlighting of the Hare Krishna slant on it.
Clothes
We can wear ordinary clothes! Apart from if you're a committed monk, then you have to wear orange dhotis.
The saris and dhotis (which look like the flowy gowns you're referring to) are more cultural.