The City used to be a great place to stay. There is a lot of crime. Larceny such as car break-ins and theft primarily, has caused a lot of stuff to close (restaurants, shops, shopping centers) and driven visitors away. The homeless are all over, and in the districts where the main hotels are located, very few tourists go out on the street so the homeless seem so visible. There is also now a doom loop discussion and on and on. Long debate, but a lot less people are willing to stay in SF. The City could come back in the long run, but it is going through a rough patch, and we would not recommend visitors stay there currently.
Just appreciate there all sorts a great places to stay outside the City . There is wine country (Napa and Sonoma) or Sausalito, for example, which we like and it is an easy drive into Berkeley. The Grand Dame hotel near campus is the Claremont Fairmont. There are a few less expensive hotels in Berkeley, which some people like, but you will never get my wife to go to. Mostly downscale. A lot of people like to stay in the Walnut Creek area, including us. Oakland has gentrified, but that is more for the young and hip who know where to go and not go. The Bay Area is expensive relative to most other places. On the flip side there is a lot to see and do. I'm sure posters can help there. If you golf, you are in a great area, especially if you have connections to some of the most famous courses in the world.
As for game day, Berkeley has great restaurants. There are plenty of Michelin rated spots, and you can go on line to see lists of all the food places to go. Some you definitely meet reservations. The slow food movement started at the famous Chez Panisse and you make reservation yesterday. Zachary's for pizza, Rick and Ann's for breakfast, Camal's and Flacco for Mexican, Great Wall for Chinese, and restaurants on College such as Wood Tavern (not that close to the stadium). There are a lot of other restaurants and views, which other posters can provide. Food is a big deal in Berkeley. Then for quick bites nearby: Top Dog is an institution, La Val's for North of campus pizza, La Barrita, Kips for quick burger or pizza, the Faculty Club (surprisingly nice and nearby). Again, I expect a lot of debate. Someone else should provide bars, the watering holes I knew have shut down (e.g., Blake's). There is a "tailgate town" in the field next to Memorial Stadium, which seems nice for kids and has a few places to buy food and drink. It is not traditional tailgating.
Fly into Oakland airport, not SF. The school is on a hill in Berkeley. Climbing the campus to the stadium is good exercise. Views from campus are outstanding, The Stadium, near the top of the hill, has dramatic views of the entire Bay, Golden Gate Bridge and the City.
Often there are water polo (a big Cal sport) or women's basketball games before football games that take place in west campus, down the hill.
There is no single area designated for tail-gate parties for visitors. There typically is lot's of small tailgates through-out campus. Tailgating is not as big as in the southern schools, and as mentioned above Berkeley has a big restaurant scene ranging from high end to Top Dog. Student wise, there are huge parties on fraternity row, and visiting fans can hear some stupidity from time to time. The stadium scene towards visiting fans is low key.
Architecturally, there are some famous buildings on campus, many funded by Hearst money, and designed and built under the supervision of the renowned Julia Morgan and John Galen Howard. The campus is a sort of a mess in terms of a master plan, but entering through the famous Sather Gate and walking north you get a sense of the historical campus.
Traditions: The pregame rally is at Sproul Plaza, which is hosted by the Cal band, cheerleaders, and dance team. After you attend the rally, you can join them in the March to Victory up the hillside to the Stadium. About 2 hours and 20 minutes before kick-off, the football team unloads off the bus, touches the Bear and walks through the crowd and into Memorial Stadium. There also is a monument to the Big Play right by the Bear statue. Some people watch the game on the hill above the stadium known as Tight Wad Hill. There is a cannabis aroma around. There also is a loud cannon which, in theory, shoots when Cal scores, and when the team enters the playing field. If Cal is going to win, you will hear the Bear Territory chant. Sometimes there are flyovers a few minutes before the game. And the cannon may shoot off, as noted above.
The game: traffic is badly controlled by Berkeley police, and when you get of the campus border, students control the campus and they know what they are doing. Parking is horrible and if you get tickets, try to get a parking pass to one of the many designated lots in and around campus. The Stadium has been remodeled and is impressive looking, and in a beautiful location, with views galore. The alumni side has clubs between the 30s, where if you have seats you have access to restaurants in the lower Field Club, and in the upper seating areas (known as the Stadium or the University Club) complimentary premium food and beverages including beer, wine and liquor. They changed the vendor for the food and beverages. The experience for many now seems to be poor, and the Stadium Club in particular has seen attendance wane. Many visiting fans now can and do buy individual seats in the upper clubs for a convenient experience (the tickets also come with premium parking near the Stadium, which is huge). This would have never been the case in the early Tedford years, where the Stadium typically sold out, but in these days with mediocre teams, the attendance in the Clubs (other than the Field Club) and overall has dropped. The Clubs have nice padded seatbacks with cupholders. Sections EE, F, FF, H, HH, and I contain bleacher seats with back support. With corner and end zone seating, it is on metal bleachers without a back. Unless attendance picks-up, you should be able to stub hub into better seats. The non-club food in the stadium actually is pretty good for stadium food. There is a lot of debate on the game experience, which other can address. We like going to games, we now sit in the field club because we like to be close to the action, and we eat in Berkeley, often admittedly at Top Dog.
Hope this helps.