The marching bands have been chosen, which parties to attend decided, and Barack Obama has picked Abraham Lincoln’s bible to place his hand on to take the Oath of Office to become America’s 44th president and the first black man to occupy the White House.

The only real question left about Obama’s Jan. 20 swearing-in is exactly how many people will show up for an Inauguration Day that many experts say will be the most attended since 1.2 million people witnessed President Lyndon Johnson’s in 1965.

Obama’s Presidential Inauguration Committee and Washington, D.C. officials have backed off earlier predictions that four to five million people could descend upon Washington, a city that attracts 20 million visitors a year.

Instead, officials in the Washington, D.C. Northern Virginia and Maryland area are plotting and bracing for up to two million people, about 10,000 buses, and an unfathomable number of cars during an Inauguration Week made even longer by the Martin Luther King federal holiday on Jan. 19.

“I think we can predict we have no idea how many people are actually going to come to the inauguration,” Washington City Administrator Dan Tangherlini said on WAMU-FM’s “Kojo Nnamdi Show” in Washington last Friday. “The biggest issue is, the factor that no one can predict, is what the weather will be (on Jan. 20). That will be the determinant to how many people will make a split decision, a spot decision that moment that 'I want to go to the inauguration.'”

To better prepare, Washington officials have even spoken to a crowd expert involved with the Hajj, the annual Muslim trek religious and spiritual to Saudi Arabia’s Mecca and the world’s largest yearly pilgrimage. Some three million people from 100 countries made the journey to Mecca early last month.

“This is a defining moment of American black history, and people want to be here to witness it. This is the biggest event in black history, something you can’t put a number on,” John Townsend, public affairs manager for Mid-Atlantic AAA, told BlackAmericaWeb.com. “It will be absolute gridlock. It will be gridlock from Richmond, Va., to D.C. and gridlock coming from the (Pennsylvania and New Jersey) turnpikes to Delaware.”

Getting to Washington by means other than car could also pose a challenge for people who haven’t already secured travel and lodging plans. Aviation officials say existing flights into the Washington area’s three major airports are near capacity. Airlines plan to add as many as 100 more inbound and outbound flights between Jan. 15 and Jan. 22.

Amtrak reports that its business is booming, with more than 44,000 tickets reserved during inauguration week on train lines that service Washington. With reservations on lines like the Boston-New York-Washington Northeast Regional up 315 percent, the Boston-New York-Washington high speed Acela Express up 161 percent, and the Charlotte-Raleigh-Richmond-Washington-New York Carolinian up 296 percent, Amtrak officials say they may expand their service.

Bus companies from Greyhound to so-called Chinatown buses, discount carriers that serve Washington from New York and Philadelphia, say they are also poised to add service to accommodate inauguration traffic.

“On Inauguration Day, we will be winging it,” Bryony Chamberlain, director of operations of Coach USA, operator of the discount carrier Megabus, told McClatchy Newspapers. “Passengers will get there, but it will take longer.”

Inauguration planners say many travelers are expected to arrive by charter bus. Regional transportation officials recently took a survey of charter bus companies within a 1,000-mile radius of Washington and determined that about 10,000 of the 25,000 buses within the radius will be in the District on Inauguration Day.

District officials are trying figure out where they will put all those buses, having never had to deal with that many motor coaches before. The record for parked buses within Washington’s city limits for an event is 1,200, and that was for the 1995 Million Man March on the National Mall.

Washington and inauguration officials have opened the Mall for Obama’s swearing-in. They estimated earlier that they could squeeze about 3 million people into the space. Inauguration officials have been scrambling to work out the details of creature comforts for the expected millions who may be confined to the Mall – a 2.5-mile park that stretches from the Capitol Building to the Washington Monument – for hours.

Officials resolved the number-one comfort decision last week: 5,000 porta-potties will be situated along the Mall and the inaugural parade route, a major task that will require crews to start putting the comfort stations in place on Jan. 17.

As for finding lodging, several area hospitality officials say good luck at this late date. Most of the area’s 90,000 hotel rooms are booked up and those that aren’t are commanding hefty per-night prices with three-and-four-night minimums.

“You couldn’t get a room even if you could pay for it,” AAA’s Townsend said.

A group of Obama supporters in Florida, unable to afford both airfare and hotel costs, thought it had a novel and affordable way of getting to the inauguration – renting a 500-room cruise ship.

Organizers of the “Yes We Can 2009 Inauguration Cruise” had planned to sail from Fort Lauderdale to Baltimore then bus the passengers to Washington for the inauguration. But the cruise is now in jeopardy as organizers are 300 reservations short to satisfy the Imperial Majesty Cruise Line, the owner of the ship.  “Yes We Can Organizers” are still holding out hope that their trip can be salvaged.

"Our frustration is that this is really a turnkey product, and it's an affordable and practical solution," Lephate Cunningham, Jr., one of the cruise’s organizing partners told The Miami Herald. "Now we just need to get enough momentum to cover the costs."

Meanwhile, Washington continues its preparations for Inauguration Day with workers hammering away at review stands outside along the Pennsylvania Avenue parade route and outside the White House.

The inaugural committee has announced that Aretha Franklin will sing at the inaugural ceremony and that the Rev. Joseph Lowery, co-founder of the Southern Christian Leadership Council with the late Dr. Martin Luther King, Jr., will deliver the ceremony’s benediction.

Dr. Rick Warren, an evangelical minister of California’s Saddleback Church, will deliver the invocation. Warren’s selection has been criticized by the gay and lesbian community largely because he supported the state’s Proposition 8 effort which banned same-sex marriage.

On the entertainment side, Obama’s inaugural committee has selected marching bands for the parade that range from traditional and funky. Florida A&M’s Marching 100 Band, the Howard University Marching Band, Hampton University’s Marching Force, and the Delaware State University Marching Band will be among the bands from Historically Black Colleges and Universities strutting their stuff along Pennsylvania Avenue.

The marching band from Virginia’s T.C. Williams High School – of “Remember the Titans” fame – will also perform along with the Brooklyn Steppers and the band from Hawaii’s Punahou High School, Obama’s alma mater.