What parts of I95 are you trying to avoid? Most of it, or just the DC metro area?
If its just the Baltimore and DC metro area, I would suggest US30 to US15S, follow that to US17 which drops you on I95 south of the DC area. If you take US29 further south it is not bad at all but it does take you South by South West into NC, from there I would pick up I74 an dlink back up with I95 north of Florance, the alternate is I85 to I77 to I26 and drop back onto I95 near St. George and continue south.
Be aware that US15 is 2 lane from Point of Rocks MD, until Leesburg, VA and then back to 2 Lanes from Leesburg until you combine onto US29 South of Gainsville, VA. Though I would not try to link up with US29 prior to that. From there south US29 is 2 lanes or more with the only real congestion point being Charlottesville, VA. From there through Danville, VA is pretty smooth sailing with few lights and traffic to deal with. I have not been down past Danville on 29 in several years to comment on that.