Across the country, corporate landlords are expanding manufactured housing portfolios and driving up rents, pushing longtime residents out. GOLDEN, Colo. — When Sarah Clement moved to the Golden Hills mobile home park two years ago, she felt like she had won the lottery. After years of squeezing into one-bedroom apartments with her, her 7-year-old son finally settled into his own bedroom, his toys splayed out in the yard and his school just at the edge of the park. Ms. Clement loved the friendliness of her neighbors and getting to watch the sun rise over the scrubby mesa to her east...