Well, it isn't legal to download it without paying. The game isn't even abandonware as last time I checked, Blizzard has the rights to the Redneck IP.
Try GOG.com. They have a bundle with the first Redneck Rampage in it, as well as Suckin' Grits on Route 66, as well as Rides Again and Deer Huntin'. And it's for a low price too.