The heat load on the AC is the sum of the conduction loss through
walls, windows, etc.
and that incurred in cooling (and dehumidifying- no small challenge in
SE VA) infiltration from leakage.

Can we assume the system was running non-stop?

Not knowing what energy-conservation measures are in place, it's a SWAG
as to what measures would benefit you most. SWAG taken.

Suggestions:
1) Replace filter- too cheap to quibble unless it's new. See that all
air-movers are moving air. Probs- see 5.
2) See that all windows, including storms are closed. Tightly.
3) Look for the obvious air-leaks, like all door-seals, especially at
top and bottom of enclosed volume of house. Chimney-effect thing.
4) Close shades, especially facing S & SW. No shades? Good
investment.
5) If A/C has not been checked/serviced within a year, schedule it now.
Better techs will be busy, and you don't want a hack/salesman. Ask
what checks or basic servicing you should do regularly.

Vaulted ceilings will make it difficult to retrofit proper ventilation,
but you might check that you've sufficient soffit vents if there's a
ridge vent. Which I'm assuming. (There really should be a "channel"
for air-flow from soffit vents, between insulation and roof-deck, out
ridge vent. To reduce heating of house and frying of shingles.)

Ceiling fan in "great room" mainly mixes hot air above with cooler
below. Sub-optimum. You'd get better perceived cooling with small
circulators moving only air down at human-level. "Vornado" comes to
mind- works for me.

OTHO, 84 vice 102 is good. :')

HTH,
J