Hi.
Regarding the hotels, I think most patients stay either in the Hotel that Yeson recommend which is near the Clinic, or in Phil House. The second one is a bit cheaper , especially if you are travelling with company. For the hotels, make sure you get a non smoker room. Some patients have used other accomodation options though like renting a vacation flat, other hotels that have a good rating - Gangnam is rather expensive though, and since you only have 3 visits at the clinic, its not really worth trying to be as close to it as possible.
Navigating the city is easy. Most signs in the city center area are in englisch as well, in the subway , everything is in englisch as well. Restaurants often have english language menus if they are in the more tourist areas, and many have pictures of the menu items. Post OP when you are mute, you can use your smartphone to make photos of menu items and show them to the waitress, or you can type in english, if you are in a tourist, international, student or shopping area. You will also get some printouts with english/korean vital sentences about food, transportation, adress of the clinic etc. You can just show and point them to anyone. Plus you can of course sign, which worked well for me.
I would definitely recommend some sightseeing. The surgery is leaving you with little pain in the days after, on day 2 or 3 you wont even notice much at all, so sitting in the hotel at that time just becomes boring. The royal palace is worth a visit, they have guided tours in english. The N Seoul Tower apparently is good. Some have done that tour to the DMZ for a day, but I skipped that one because we kind of found this sort of tourism a bit weird and expensive. There are a few temples and museums to see and the Hangkok village.
I think singing certainly works, how well it really works, especially in terms of being professional and how easy it is to hit the right resonance, others have to say. I think resonance generally is still an issue post op - most of the post op exercises seem to aim at changing the resonance towards more female patterns. The size and length of the area between vocal folds and mouth cannot be changed by surgery, but has to be dealt with by training.