Thought you'd never hear His Rocky Mountain Highness sing "funky music gotta stretch your soul"? Well, faaaaaarrrr out: Denver's disco debut is a Bee Gees-tinged thumper in which he acknowledges the "dancin' fever" but specifies: "I am one who dances with the mountains/I am one who dances in the wind/I am one who dances on the ocean..." When it isn't boogeying up the Rockies in platform shoes, though, this superbly produced (by Milton Okun) LP is another celebration of the great outdoors, whales and mountain girls. It is as warm and pretty as a sound track for those Wilderness Family movies. That may help recoup Denver's wholesome image, damaged last year when an Aspen, Colo. newspaper called him an "eco-twerp" for installing a 4,000-gallon gas tank at his home, and again this winter, when he shot at two dogs with a BB-gun after they began nosing around his garbage cans and "giving my little dog a hard time." There are a couple of schmaltzy ballads, but John is stirring on American Child, and this LP is a reassuring recovery from his Christmas collaboration with the Muppets.