This is pretty interesting - where did you read about them talking about fighting Lee in the Wilderness?
I have seen it in a few places over the years and there is a point in an April letter to Meade from Grant in April where Grant describes his plan for the campaign (overall and then specifically for Meade). In it, he says that they will go over it in person. I will check to see if I have a more specific reference.
The sequence in the Wilderness is reflected in these messages on May 5th:
HEADQUARTERS ARMY OF THE POTOMAC,
Old Wilderness Tavern, May 5, 1864.
(Received 7.30 a.m.)
Lieutenant-General GRANT:
The enemy have appeared in force on the Orange pike, and are now reported forming line of battle in front of Griffin's division, Fifth Corps. I have directed General Warren to attack them at once with his whole force. Until this movement of the enemy is developed, the march of the corps must be suspended. I have, therefore, sent word to Hancock not to advance beyond Todd's Tavern for the present. I think the enemy is trying to delay our movement, and will not give battle, but of this we shall soon see. For the present I will stop here, and have stopped our trains.
GEO. G. MEADE.
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HEADQUARTERS ARMIES OF THE UNITED STATES,
Germanna Ford, May 5, 1864--8.24 a.m.
General MEADE:
Your note giving movement of enemy and your dispositions received. Burnside's advance is now crossing the river. I will have Ricketts' division relieved and advanced at once, and urge Burnside's crossing. As soon as I can see Burnside I will go forward. If any opportunity presents itself for pitching into a part of Lee's army, do so without giving time for disposition.
U.S. GRANT,
Lieutenant-General.
Major-General WARREN:
I send you the above. Wright is advancing on the Spotswood road. Attack as soon as you can, and communicate, if possible, with Wright.
GEO. G. MEADE,
Major-General.
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HEADQUARTERS ARMY OF THE POTOMAC,
May 5, 1864--9 a.m.
Lieutenant-General GRANT:
A Mr. Wyckoff, a Northern miner, whom I have met and believe to be reliable, has sent me word that a person from Orange Court-House yesterday told him that Breckinridge and Polk had joined Lee. I send you this for what it is worth. Warren is making his disposition to attack, and Sedgwick to support him. Nothing immediate from the front. I think, still, Lee is simply making a demonstration to gain time. I shall, if such is the case, punish him. If he is disposed to fight this side of Mine Run at once, he shall be accommodated.
GEO. G. MEADE,
Major-General.
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HEADQUARTERS ARMY OF THE POTOMAC,
May 5, 1864--9.20 a.m.
Lieutenant-General GRANT:
I ordered General Ricketts to hold the roads leading from the enemy's line to our right flank. I am informed you have ordered him forward as one of Burnside's divisions has arrived. I would suggest Burnside's division relieving Ricketts' on the roads, also a small party of cavalry I have in front of Ricketts. Ricketts having received my order after yours is awaiting your action on this suggestion.
GEO. G. MEADE,
Major-General.
There is no difference between them here unless it is on minor details. They are of one mind: the enemy has shown up -- hit him.