When the Overland Campaign started, there was only a general plan of campaign for the Virginia campaign. It went like this:
- Grant/Meade would move on Richmond, assuming would move to attack them or to interpose between the their advance and Richmond.
- Sigel would push up the Shenandoah, threatening Confederate sullies/LOC and acting as a possible turning reinforcement for Grant/Meade
- Butler (really Smith and Gillmore) would move on the Petersburg-Richmond RR line to cut the Confederate LOC
- Crook and Averell would lead expeditions against the Confederate RR/LOC from West Virginia.
This fell apart quickly, with Breckinridge routing Sigel and Butler blundering into uselessness at Bermuda Hundred. Averell was stopped at Cove Gap, but Crook tore up the RR and burned the New River Bridge before returning to WV (hearing that Lee had beaten Grant at the Wilderness.
That left Grant/Meade. They were marching quickly, trying to get through the Wilderness and get to better territory. Lee moved to strike them hard, wanting to see if he could pull off another Chancellorsville. Grant and Meade had discussed what to do and were on the same page: if Lee came into range, fight him!
So when the AoP is in the Wilderness and Meade hears Lee is approaching, there is no hesitation. Meade calls off the advance, pivots the army to the West, and moves to meet Lee. After he issues those orders, he notifies Grant of what he has done.
Two days of bloody battle later, Grant looks out across the smoldering Wilderness, sees the Confederates digging in, ready for more fighting. He mutters "After two such days, Joe Johnston would retreat." That night, Grant pulls the AoP out and marches SE. When the army realizes that they are not pulling back to Fredericksburg but pushing towards Richmond, the troops erupt in cheers. Finally, they have commanders who will keep up the fight, who will lead them against the enemy until the war ends.
That takes us to Spotsylvania and the bloody fighting there. Grant sends Sheridan on his raid towards Richmond; Lee detaches Stuart to counter Sheridan and Stuart dies. Fighting around Spotsylvania continues day after day, Grant hitting Lee left, right, and center. Grant wants to keep Lee tied in position and neither has enough cavalry present to engage in a real campaign of movement. Grant would gladly crush Lee and comes close a time or two (particularly at the Mule Shoe); Lee defends with grit and skill.
When Grant gets the reports of how things have fouled up in the Shenandoah and at Bermuda Hundred, he realizes it is all up to the main force. He starts the series of turning movements that take us to the North Anna, Cold Harbor and Petersburg. In those days, they used to call this campaign the "Forty Days" as a reference to the suffering and trials of the Bible.
The campaign of Grant and Meade came close to breaking Lee more than once. Confederate disaster loomed overwhelmingly in the days before Cold Harbor and then again at Petersburg. Hard fighting, General Lee, overall exhaustion of the soldiers and plain luck saved the Confederacy in those dark days.
There was no specific campaign plan drawn out beforehand. Grant and Meade acted on general principles and ideas. They knew that every step closer to Richmond was a blow to the Confederacy. They knew what Lee knew: that Lee needed room and distance from Richmond to wage the campaign of maneuver he favored, that the more tied to Richmond and Petersburg the ANV became the less of a threat to the Union they were. While Grant must have wanted to avoid a siege and win quickly, Grant must also have known a siege would grind slowly in favor of the Union.