If I was able to reintroduce Sliders, my pilot would take place in two different, but similar worlds.
Earth A: For lack of a better place, our world. Pretty much the same timeline, with maybe a few very small changes. Home of Quinn Mallory (A), Prof. Maximillion Arturo, Wade Wells, and Rembrant "Crying Man" Brown.
Earth B: Same as ours, up to 2000, where Jeb Bush was elected President of the US, but Bob Dole had been Reagan's Vice-President. Home of Quinn Mallory (B), his brother Colin, Col. Maggie Beckett, and Dr. Diana Davis.
In both worlds, the Quinns where working on anti-grav experiments. Quinn A was doing it as a hobby, and Quinn B as part of a new type of Stealth Fighter. They fired them up at the same time, and where fused into one person. The side-effect is that A brought along Prof. Arturo, Wade, and Rembrant; and B brought along Colin, Maggie, and Diana. They all land on a third version of Earth, which will become their base of operations. The fused Quinn can find and open portals(wormholes).
The villan would be Logan St. Clair, whose Earth is under the fist of a facist corporate state. She wasn't sucked in, but was the cause of the event. She, and her followers travel the on an large, omni-terrain base; picture something like the SHIELD Heli-carrier, but with ground movenment capiblity.