Most of the description is cut short by the Anime. For example Kirito's inner monolouge during his last duel where he figures out the sword is weak due to the decorations, hence why he can broke it into two. Also the fight in the dungeon with Asuna where they explain the switching system was fare more detailed in the novel. Anime one is... blegh

minimum age to play SAO is around 10/11 i think, so right now they're 12/13. and most people got scared knowing they would die, thus decide to just stay at town of beginning until the game ends

and yes, most people at town of beginning decide to just hide in their home most of the time since the army usually tries to extort some money from them(there are ways to gain some money without leaving the town, even if its small)