I just did a bunch of work on a Surf Champ, great game.
If you haven't, but a NEW ball for it, the old one may be pitted or have rust which will tear up the playfield.
Clean the playfield with Novus 2 after vacuuming up any big dirt with a vacuum and soft brush. Give it a good wax with a hard carnuba wax with no added cleaners after. Clear coat is great but not necessary in a home if you want to avoid it.
Clean the plastics with Novus 1.
First thing I would do, and I was told to do this by a man much smarter than myself, clean all of your stepper units. There is a coin stepper in the bottom of the cab, a bonus stepper under the playfield, a players stepper in the back box, and 3 out of the four score reels for each player has a stepper.
For the first three steppers I mentioned, use 3 in 1 oil on all of the pivot points, the grease they used in the factory solidifies after years and this is a must. You want them moving freely. Then you need to remove the bakelite disc with the shoes on them and wipe alcohol on the rivets with a rag, then use a green 3m scotchbrite pad right away to get them nice and shiny, buff the shoes with the pad too. Then use a thin layer of superlube on all the rivets after that. make sure you note the position of the disc with the shoes and replace it the way it was, especially on the player unit, and don't step the unit and that one up while you have it taken off as it is a continuous stepper unit that wont reset back to home, you don't want to lose the position.
The score units don't have pivot points, but they have rivets that need cleaning, you remove two screws and a little C clip to clean those. Put a white sheet down so that when you drop a C clip you don't spend half an hour on the floor hunting for it.
Clean those before doing anything else.
More info here: http://www.pinrepair.com/em/index2.htm#steps
Happy to help if you have any questions.