Residents say they want $1,500 per square meter, or 15 hectares slotted for themselves in the new development.
Nearly three quarters of all the rapes involved girls under the age of 18.
They were charged with illegally crossing the border and entering a military area.
More than 1,000 of 4,000 families have already been evicted or have moved from Boeung Kak lake area.
Richardson's visit follows a high-profile trip by US Secretary of State Hillary Clinton in November.
Members of the Thailand Patriot Network gathered in front of the Cambodian Embassy to call for the release of the group.
Meanwhile, the National Election Committee has been accused of weak enforcement of the Election law.
The reporters killed include those who supported the opposition parties, as well as the pro-government newspaper Koh Santepheap.
The charges carry a sentence of three to six months in jail and a fine of up to $500.
An independent analyst says Cambodia could see growth as high as 10 percent in coming years if governance is improved.