Let as assume that Caesar did not care to conduct a "March across the Rubicon" with the Hoover Dam, and instead wanted to take Vegas in the least amount of time, with the largest amount of his Legion alive. What would be the proper manner to perform that action? After giving it some thought I had always assumed that the Legion could simply tie up the NCR military further in Arizona, continue covert operations in Southern Nevada (such as Nipton and Ranger Station Charlie, and the Omerta operation) and fund a major plain clothed counter insurgency against the NCR at McCarran and their supply lines in the area, all calumniating in the Omerta/Monorail Plot that would be supplemented with riots in Freeside and a Tet Offensive style attack on the other NCR positions in the Mojave leaving them unable to respond to the crisis of the Strip.

Do you think the Legion had any other military options in the Mojave?

Tet was a military disaster for the North Vietnamese....as Caesar has no Walter Cronkite to carry his water for him doing the same thing would be a political disaster for Eddie too. To win Eddie needs the NCR to nerf itself by forgoing every advantage they have and then adopting a military strategy of breathtaking stupidity...basically the situation the Courier finds when he/she wakes up on the cot in Doc Mitchell's surgery.

In short....he has to do nothing, the situation is already developing to his maximum advantage.