If you plan to take I-64 to where it merges with I-81 and then I-64 past Richmond and on to Williamsburg, you will find that in Waynesboro, VA, there is a Walmart, a Home Depot and a Lowe's that might possibly be able to accommodate you, but I would call and speak with the manager to get a pre-approval.
On across Afton Mountain,there are several campgrounds right off the highway outside of Charlottesville. We overnighted at Misty Mountain RV Resort last year. Pull-thrus that were large enough that we didn't have to unhook. Exit 107 off of I-64.
From Charlottesville until you get into Richmond, there is not a lot of anything and that is probably further than you want to drive.
