I'll try to break these down for you. Coax - How most people connect their VCR's to their TV's, also how cable TV is broadast. RCA to BNC adapter. S-Video experiences quality loss if you try to run more than 100'. I've experimented using S-Video vs. RCA and have experimented negligible difference in the presentation.
Surfaces can range from walls, drapes, makeshift screens, and pro-screens.
Proscreens are the best, but can get damaged easily, and are very expensive. The screens of choice are Da-Lite fastfolds. Walls are good as long as the wall is white, and long throws on walls usually results in a dim image. One corner of our home-made screen frame. We used metal piping with screws to secure corner piece to pipe sides.