We go to Williamsburg all the time and have a family of 5, so we need 2 beds plus a sleeper sofa, too.
We like the Country Inn and Suites on Bypass road - they have a "suite" that has the extra sleeper sofa. There is also a Marriott Residence Inn and a Marriott Springhill Suites that are on route 60 very close to downtown.
We stay a lot at the Holiday Inn Express and Suites on Route 60. It is right at the end of Bypass Rd and they also have a "suite" that has the extra sleeper sofa. We've always been able to get very good rates there and they are a nice/clean hotel.
I can also vouch for Powhatan Plantation and Greensprings for timeshares - both very nice.
We love Williamsburg! Have Fun!