|Well The Civil War Notebook of Daniel Chisholm, edited by W. Springer Menge and J August Shimrak, has quite a bit of what you want. Chisholm and his brother Alex served in Company K, 116th Pennsylvania during that time and after the war he collected both his and his brother's letters home in addition to making a copy of the diary of Samuel Clear, a fellow Co. K vet, as well as an excert from Lt. James Cope's diary, Cope being one of Co. K's officers who was taken prisoner at Petersburg. Chisholm's notebook was put out in 1989 by his descendant W. Springer Menge.
Here's a couple of Clear's diary enteries:
Thursday, June 16th, 1864 -- In front of Petersburgh, Va
We got up early marched 2 miles and halted. I took a detail and went back after rations. Our rations had not come but we borrowed one days rations from Burnsides Corps in the evening late. At noon I had gave a teamster twenty five cents in silver for 5 fardtack, reported back to the Division and soon got shut of out rations, fell into line and charged the rebel lines with Burnsides Corps. Carried their works, worked all night at entrenching.
Saturday, March 25th
This morning hard fighting on the right. The rebels under Genl Gordon charged on Fort Steadman whis was garrisoned by the 14th N.Y. Artillery at daylight and took them by surprise and captured the fort and turned our guns on us. We was ordered under arms at daylight. Instead of us going and reinforcing the 8th Corps the 2nd & 5th Corps advanced over the works in front of them and attacked the rebel picket line, charged and took and held it in spite of all they could do. They tried time and again to drive us out but could not do it. The 148th P.V. with seven shooters had the advance and when they started they did advance as skirmishers nicely and made the Rebs more than fall back and leave the first line. And when we came up we charged and took the main line and held it until twelve O'Clock P.M. We then fell back to the old works and stood under arms until daylight. While this was going on with us the 9th Corps charged and took back their Fort Steadman and captured all the rebs in it. Our advance was to draw the rebs away from the front of Steadman so the 9th Corps could take back the fort.