Congrats on having 2 great options, @HMom16!
Dorms/houses at SPS really vary a lot depending on the building so it makes it hard to say. Not surprisingly, the best rooms go to upperclassman. I will say, that in general, my kids had great housing with clean, well-maintained bathrooms and communal kitchens and common areas in each dorm. I can’t think of any with narrow hallways and low ceilings as that doesn’t fit the description of the dorms my kids lived in. There is one boys dorm that has a reputation for being a bit dreary so maybe that is the one your son saw. In general, BS dorm rooms tend to be much nicer than freshman college dorm rooms.
Most freshman have doubles although there are a just a few triples and some singles available. There is more selection with seniority. Once you get past freshman year, it is pretty easy to get a single if you desire one.
Workload is manageable depending on one’s organizational skills and discipline, something my kids didn’t win prizes in. 
A little bit social. I wouldn’t say it is any worse than a rigorous public high school. Workload tends to creep up each year. I would expect 3 or so hours per night, some nights more, some nights less. Taking advantage of free periods to study and getting a little done in the afternoon can help with the management. My kids had friends and classmates that went to bed every night at 10PM and did well. My kids weren’t so disciplined.
Food is quite good. Every place can get a bit repetitious after awhile but my kids were generally happy and since there is a range of options, its easy to find something to eat that you like. In addition to multiple hot offerings, there is always an extensive salad bar, a pasta bar with a choice of pastas and sauces, a stir fry station, a station for making a variety of sandwiches. Serve your own ice cream. The desserts are quite good and I always found them very tempting. The school goes all out for special dinners which happens quite frequently. For breakfast, you can get made to order eggs/omelet bar, waffles, etc. Sunday brunch is everyone’s favorite for great food and hanging out and relaxing with friends. They try to use local foods where possible getting fresh upscale bread from a bakery in MA and cage free eggs from Maine, as two examples.
Yes, advisors are tied to dorms. Most kids will wind up with 2ish advisors over their 4 years due to dorm switching although some will manage to stay in a dorm for all years and keep the advisor relationship if it is working for them. Both of mine had 3 advisors in their 4 years, some due to kiddo switching dorms, some due to faculty changes. All were decent to fine. Others have reported having WOW! relationships with their advisors but my kids either didn’t seek that out/need that kind of connection or didn’t have that luck.
Let me know if you have more questions as you make your decision. Are you too far to make another visit? Do you not have until 4/10?