Hi, I have a son and daughter currently at a large coed boarding school, son in his last year and daughter midway. My son has friends from his prep school who have gone to all boy schools which are a little more traditional.
Dorms are allocated by the housemaster. Your dorm mates are always from your year group. In the first year some schools now keep all the new boys in one house. This is to avoid the possibility of older boys pranking the young boys or bullying them. The new boys (age 13, year 9) get to know their year group, their way around school and then in year 10 they move up to their senior house where they remain for 4 years. Most schools you choose your senior house years earlier during the admissions process. The more traditional boys boarding schools you go straight to your senior house and stay there for 5 years. 60 boys in a house is probably the average. A house is all age groups. Some schools different houses have different ties and they eat in house. Most schools now you eat all together in a dining hall, year groups are given different sittings.
1st year dorms are usually 4 beds and an allocated bathroom en-suite or in the hallway. Apparently Radley first years are in a long room of beds with curtains around each cubicle. Each term you move dorms. After the first term you are asked to email a list of 3 names who you would like in your dorm. You usually get one of those people. After GCSEs you are in a room of two (you choose who with) and your final year you have your own room. Again every school is different, Eton you have your own room for all 5 years apparently.
As well as the housemaster there are 3 residents (teachers) who sleep in house. Matron is 9-5 and supervises cleaning staff and the domestic side of things.
Boys usually know a couple of other new boys from their prep school days or from meeting at a neighbouring school playing matches over the years. Boys coming from state school is no big deal, no one cares, it’s a very busy environment and you are flat out and tired in your first year. There is often someone who sneaks a phone into their bed, a quarrel when someone wants a window open in winter … so sleep is disturbed.
First years usually have prep supervised in a big room. Second years and upwards can have a desk in their room.
Hope that helps. I am not from a public school background so have picked it all up from my kids over the years. My kids are home after matches every Saturday evening and back in school for Sunday evening. We are 50 mins from their school so it’s doable. Fewer and fewer schools and parents now send children off in September and don’t see them again until half term.