With the clock ticking toward a Feb. 21 deadline, residents of the 160-member historic Hillwood Square residential development on Cherry St. between Rt. 50 and Hillwood Ave. continue protesting the prospective sale of the entire 20-acre property for demolition and redevelopment into a 455-unit rental project by Archstone, a Denver-based company owned by Lehman Brothers Holdings Inc. of New York. All 158 families housed in the affordable units there would be forced to move according to the terms of the imminent deal, which would be for for $38 million. Residents say the $38 million is far below what the property is actually worth, but in a Feb. 1 memo they were told it was the best deal available, and some residents are being offered the payoff of underwater mortgages in order to obtain enough support for the sale.