PERSONNEL FILE . . . L. Randolph Williams of Randolph Williams Inc. of McLean has been installed as the 1983 president of the Northern Virginia Builders. Joining him on the group's executive committee will be William L. Berry of William L. Berry & Co. Inc., first vice president; F. Gary Garczynski of Scarborough Corp., second vice president; Fulton R. Gordon III of The Gordon Builders and Developers Inc., treasurer; and Sidney O. Dewberry of Dewberry and Davis, secretary . . . John W. Farrar has been promoted to vice president of land development by the Reston Land Corp. He will supervise Reston Land's infrastructure and capital improvements program--roads, utilities, lakes and the like . . . James W. Kibbe has been named senior vice president of Weaver Bros. Inc. Sales and Leasing Town & Country Realtors has appointed Larry Barnett manager of the firm's Vienna office . . . Mount Vernon Realty Inc. notes that John T. Simpson, a Realtor specializing in investment real estate, has gone into the securities business as a registered representative with Mount Vernon Equity Sales Inc. . . . Edward F. Godfrey, former president of Equitable Life Mortgage and Realty Investors, has joined Federal Realty Investment Trust as executive vice president snd chief operating officer . . . Patricia Miller has become a member of the corporate staff of Coldwell Banker Routh Robbins-Realtors. She will be director of special projects . . . Cushman & Wakefield, Inc., has elected Gordon H. McCollum Jr. to the firm's board of directors . . . John Broda, recently retired as development coordinator for the Maryland National Capital Park and Planning Commission, has joined Loiederman Associates, Inc. Loiederman is a land planning, civil engineering and land surveying firm based in Rockville . . . The Ryland Group, Inc., reports that John Slayter has come aboard as director of research, engineering and technology. He was most recently chief operating officer of the Glendale Corp., a Canadian builder of manufactured homes . . . Merrill Lynch/Chris Coile announces the appointment of Molly A. Mercer as corporate account representative for the firm's relocation services in the Washington/Virginia area. IN THE BUSINESS . . . The Reston Land Corp. reports a banner year: $13.2 million in gross land sales, the best year ever in that department; more than 100 new homes and condominiums sold, best since 1979, and completion of over more than 1 million square feet of commercial/industrial space in 15 separate projects. And to top it off, Reston Land won two 1982 first-place and one second-place MIRM (member of the Institute of Residential Marketing) awards at the recent Home Builders convention in Houston. The firsts were for "best sales office" and "most innovative marketing program," and the second was for "best advertising and promotional campaign . . . The Milton Development Co. has named Lewis & Silverman exclusive agents for its 140-plus townhouse development at Bristol Woods at Daventry in Springfield . . . Long & Foster Realtors have announced that 1982 was the best in its 14-year history, with residential sales up 15 percent over 1981. Total volume was $1.18 billion on sales of 12,118 homes . . . Meetings coming up: The Maryland Association of Condominium Owners is holding a meeting Monday evening in New Carrollton on "Pleasures and Pitfalls of condominium ownership." For information, call 345-9543 . . . Shannon & Luchs, Realtors, will hold a real estate career night Wednesday at their Dupont Circle office. Information: 466-8650 . . . The Manufactured Housing Institute will be holding its annual meeting March 28 and 29 at the Hyatt Regency here . . . Cushman & Wakefield has been appointed as the property management agent for Prudential's 200,000-square-foot office building development at 4250 Connecticut Ave, Van Ness Station . . . Bethesda-based CEI Construction, Inc., has bought operating assets and interest in contracts totaling $39 million from the Edward B. Fitzpatrick Jr. Construction Corp., a New York heavy contracting firm.

ON THE MOVE . . . Manarin and Odle Realtors, Inc., will be relocating its offices 400 South Washington St. in Alexandria, the former site of the Alexandria Chamber of Commerce. The firm currently is at 277 South Washington. The move is scheduled for mid-April . . . The National Geographic Society has leased 15,000 square feet of office space at 1730 M St. NW and 6,200 square feet at 1150 17th St. NW. The Charles E. Smith Cos. negotiated the leases . . . The Institute for Defense Analyses has subleased 67,000 on the top three floors of 400 Army Navy Drive to the Defense Department. The transaction completes the subleasing of 111,000 square feet in the 10-story, 222,000-square-foot building, which wformerly was IDA's headquarters. Arthur Rubloff & Co. represented IDA in the deals . . . The "light rock" radio station WLTT has moved to Georgetowne Office Park from its old location in Chevy Chase. WLTT is consolidating all its operations except transmitter under one roof in the move, taking three units of the new office condominium complex. Its new space totals 4,000 square feet . . . Wang Laboratories has leased 11,000 square feet at 1300 North 17th St. in Arlington. Julien J. Studley is the exclusive leasing agent there.