Gen. Lee was a southern gentleman and did not believe in living off the country side as Gen. Sherman did. If you ever have the chance to read about the foraging done by Gen. Sherman's army it will disgust you at the way they treated citizen's.
Although Gen. Jubal Early told the town of Chambersburg,Pa. that if he did not recieve one million dollars he would burn down the city, he ended up taking what he could carry off after getting a small amount of cash from several locals, the he burnt the buisness district to the ground.
The end result is that Gettysburg was no more than an excursion for shoes that turned sour. Had Gen. Jackson not been gunned down by a member of the 18th N.C. a month earlier, hH would have taken the hill that Gen. Ewell failed to take and took the high ground.
It's very doubtful that Jackson would have been able to take either Culp's Hill or Cemetery Hill. Jackson would have faced the same issues. Much of the 2nd Corps was completely disorganized and scattered within the town, or trying to reform north of the town. Johnson's Division, the only major unit under Ewell that had not yet been engaged, stretched back for three miles. It would take several hours to get up, form up and attack up Culp's Hill. In the meanwhile, there was a Union Brigade already on the Hill, digging in and building breastworks.
As to attacking Cemetery Hill, Buford's Brigade (having suffered only 127 casualties fighting much of the day) had been shifted to the north base of the hill and drove off two Confederate Regiments of Smith's Brigade that had formed up south of the town. Buford advanced his troopers, whose breach loader carbines put down a Division sized volume of fire, causing the Confederates to break and race back into the town.
By the time that the 2nd Corps was reasonably reorganized, there were in excess of 13,000 Federal Troops on the two hills, with the Slocum's Corps coming onto the scene. Not to mention the three dozen guns of Union artillery already in place. I'm convinced that any piecemeal attack on either hill would have repulsed with severe loss. Besides, Hancock was in command, and he was hoping the Confederates would do exactly that. Lee lacked good intel on not only Union strength on the hills, but on the organization of Ewell's beat-up Corps. Rhodes's Division was shot to pieces. Early's division was scattered and beat up. Billy Smith withdrew his largely unbloodied Brigade from pursuing the retreating remnants of the 11th Corps after Buford chased his soldiers back into the town.
I have no confidence that Jackson would have had any success in place of Ewell....