there are 3 main beer gardens in sapporo operated by the 3 main beer manufacturers:
Sapporo Beer Garden: At the Sapporo Beer Museum. Alight at Higashikuyakushomae (æ±åŒºå½¹æ‰€å‰) subway station on the blue Toho line (æ±è±Šç·š) and walk 10min, or take the Beer Museum bus from Odori or Sapporo Bus terminal.
Kirin Beer Garden: Alight at Nakajimakoen (ä¸å³¶å…¬åœ’) subway station on the green Namboku line (å—åŒ—ç·š) and walk <5min.
Asahi Beer Garden: Alight at Nango 7chome (å—éƒ·7ä¸ç›®) subway station on the orange Tozai line (æ±è¥¿ç·š) and walk <10min.
At the beer gardens, people usually eat Genghis Khan, which is lamb and veg table BBQ. If you think you don't take lamb, don't worry. The lamb there is so fresh it doesn't smell or taste like the lamb/mutton we have in sg at all. Just very fresh and tender meat with sweet and juicy vegetables.
You can get a Genghis Khan buffet for between 2500-5000yen/pax, depending on the quality/type of meat (seasoned or not) you choose, and whether you opt for free-flow beer.
Lake Toya and Noboribetsu are near by Hokkaido standards lah. The distance is farther than travelling across singapore but <40min on the JR train is relatively near.
I usually recommend staying at Lake Toya because I think that most of the hotels there give you a good view of the lake. I'd recommend Toya Kohantei if you're thinking of staying the night there. The view from the outdoor tubs are absolutely breathtaking. Erm, but I heard that the view from the men's onsen is nothing that great.
Basically, you can get good food at many places. But typically, you get the best seafood either at the morning markets like Nijo Fish Market at Odori in Sapporo, or along the street in Otaru. Otaru is a eat-as-you-walk place, famous for sushi, roadside freshly grilled gigantic scallops (100yen each!!), roadside steamed crabs (500yen only for one big plate!! they'll be in season in Nov!!)... And I mentioned Genghis Khan above which is also a must-try. Even the meat that comes without seasoning tastes really yummy, not to mention the sweet and succulent vegetables.
If you've never tried Japanese ramen, then you can probably give it a try, but in all honesty, you can get better ramen elsewhere in Japan. Sapporo ramen tends to be more oily.
What else... oh snacks to buy as souvenirs. There are a million and one kind to buy so make sure you bring an empty hand-carry with you!