DC - Room rates vary widely at the casino hotel. Weekends are pricey, big name concert weekends even more so. A $170 midweek room goes for $550 on the weekend. Those are rack rates, and I'm sure they can be beat. I don't think we have paid more than $250 a night for a view room. The brand new Mohegan Sun Hyatt nearby has rooms for under $120.
Those are not "cheap" room rates, of course I don't know if folks could do or did better in Hartford (the years we went, we paid with reward points). The times when I paid over $250 per night (or close to it) were special. Celebrations, resorts in Hawai'i, etc. For routine travel, we look for rates around $100.00, especially for a mulitiple night event. I would think that most would find the Sun pricy.
FWIW, we did stay there years ago ( the WBB team that played there before the Sun, small league) and thought the hotel and casino (we don't gamble) quite nice, the food at the time was good, but it was many, many years ago.