• Escape to Dreamland, 9-10 p.m. Sunday, WLRN-PBS 17

Because I grew up halfway across the country in the middle of a desert, my knowledge of Florida's sultry southern tip was vague and tenuous. For years my dominant and perhaps only mental image of South Florida was grubby tenement rat Dustin Hoffman's quiet expiration in the back of the bus at the end of Midnight Cowboy, the beaches he dreamed of shimmering delusively in the background.

My path began crossing Florida over 30 years ago, and I've seen a lot more of it than Hoffman's Ratso Rizzo saw from his Greyhound seat. But watching Escape to Dreamland, a derisive yet affectionate documentary on the Tamiami Trail that debuts Sunday on WLRN-PBS 17, I'm not sure that Ratso didn't teach me everything I needed to know about South Florida: its irresistible allure for con men and hustlers and the terminally daffy, its picture-postcard facade and its tawdry, pulp-detective soul. Its history is a repetitive tale of dreams shattering against reality (and, occasionally, vice-versa), a tale delightfully and delightedly told in Escape to Dreamland.

Neither tourist-agency brochure (''Florida really has historically been an outpost that attracts these quirky, unusual, sometimes outlandish, sometimes unpleasant and dangerous characters,'' notes one historian) nor elegaic essay on the diversity of the ferns of the Everglades (``It's a muddy mix of swamp and prairie, filled with snakes and alligators and swarms of mosquitoes so big and bloodthirsty they drove the first explorers nearly mad''), Escape to Dreamland can be as biting as the insects it describes.

Written and directed by Florida journalist Timothy Long, this film is nominally the story of the Tamiami Trail, the 275-mile highway completed 80 years ago this month that linked Tampa and Miami (the word Tamiami is not a secret, sacred Indian term but a contraction of Tampa and Miami). But because the Trail was inextricably bound up with the attempt to sell the festering, fetid Everglades as a fun-in-the-sun dreamscape -- ''Goodbye, infernal swamp; hello, tropical paradise,'' as Escape puts it -- the documentary inevitably spends much of its time pondering the region's sketchy and eccentric history.

First finding: There's a good reason nobody ever made a Cinerama epic called How South Florida Was Won. The opening of the country's western frontier was driven by ''the dream of owning a farm,'' observes John Rothchild, the author of Up for Grabs. ''It was hard work and your own enterprise and you could get ahead. But when people started turning south, mostly to Florida, the dream was sitting on a patio with a drink and not being cold.'' That is, we were settled not by hardy pioneer stock but a mass of indolent and gullible swine.

Many fortunes were made -- and some lost -- in an attempt to play them for suckers, peddling waterfront lots that were actually underwater lots. The Tamiami Trail was the greedy and somewhat nutty vision of a pack of huckstering developers who owned vast over-hydrated swaths of the Everglades and were convinced they could sell them all at premium prices if only somebody would build a road into the damned thing.

When one of the first surveying teams got lost in the Everglades and emerged two months later in Key West (surely these men were the spiritual forefathers of the Florida Department of Transportation), the developers realized no sane person would put his money into the project -- that's what governments are for. Twelve years and 100 million of today's dollars later, road crews finished blasting and dredging and scraping their way through the swamp -- just as the Florida real-estate boom of the 1920s collapsed after one hurricane leveled Miami and another blew Lake Okeechobee over its dikes.