Leon is a real cool little city and it is amazing what goes on behind all of those imposing doors. Behind each one is a charming little courtyard. If you are going to get a hotel room. Go away from the centre of town a little bit and you will find some amazing bargains that give you everything. Like a hot shower and television and breakfast for four dollars and fifty cents everything. Take a walk a little farther out of town when you can. If you like to drink sodas and walk with them, carry an empty plastic bottle with you to pour the pop into. They won´t let you leave the store with the bottle and there is nothing worse than having to walk around with a sandwich bag full of Sprite.
There are some amazing churches there. Also, leave half a sandwich somewhere and see just what type of person eats the other half. Shocking.
Managua is now centred around a giant shopping mall. If you ask for the centre of town from where the bus lets you off, this is where you will go. It is worth it to walk around from there but you are better off to ask for the big church that is the centre of the old town. Much of Managua is rough looking. Be confident, and I assure you, you won´t end up with a shiv sticking out of your ribs.
Never went to Granada. Sorry.
Back to the school thing. If you are looking for a place that has the culture in spades and there is not a million other backpackers. Leon is the place for you. That is the place. Go to Leon. Have I mentioned that Leon is good?