Carrying what supplies he could, Lee advanced from the Rappahannock into Pennsylvania, planning to live off the land once he exhausted,
what he carried. As noted, he aspired to a standard of 34 wagons per 1,000 men for this period. At the same time, he acknowledged the difficulty of acheiving this goal. The fact that lowered the goal to 28 wagons per thousand on July 12 leaves room to speculate that for the Gettysburg campaign, he probably acheived a standard of around 30 wagons per 1,000 men, for a total of 2,950 wagons. The assumption is that Lee's objectives bore some resemblance to deteriorating realities. With 89,000 men aggregate present at the start of the campaign and hence dependent on the transportation and supply system, by John Moore's calculations Lee had near exactly the capacity, with standard rations and forage, to move his army-provided he didn't send empty wagons back for resupply but refilled them off the land, which was his plan. And with numbers declining through the campaign owing to desertion, the demands on the transportation and supply system lessened." [pp. 137/8]