Ask Mr. Smarty Plants

This is a really tough challenge and I am surprised to hear that you can even grow weeds.  Although I am familiar with your area (not all the Green Gurus live in Austin, TX; we just wish we did!) I decided to search our Native Plant Database to see what native species fit your criteria.  Entering your conditions into the Combination Search (PA, dry conditions,  0-1 ft, evergreen and plants of all habits and duration) a list of only 3 plants is generated:

Coreopsis lanceolata (Lanceleaf coreopsis), which is really not what you are looking for, but makes the list because it is so adaptable and is evergreen in parts of its very wide native range.  It would be a great plant for your perennial flower garden.

Lycopodium digitatum (Fan clubmoss), whose "cedar-like appearance, low growth, evergreen leaves, and spreading habit make it ideal for the well-drained eastern woodland landscape. Once established, it spreads quickly by stems that lie just at the surface of the soil."

and

Mitchella repens (Partridgeberry), "A most attractive woodland creeper with highly ornamental foliage, it can be used as a groundcover under acid-loving shrubs."

Not a lot of choices, but either of these plants, if you can find them in retail nurseries, would be a great alternative to weeds or gravel (your other two choices).  Neither plant would be a risk to your pets, but we can't guarantee that native wildlife will avoid them.  Native animals and native plants are usually found together.

Visit our Suppliers Directory to search for Native Plant nurseries in your area or check with the Pennsylvania Native Plant Society to find sources of these plants or other natives.  Although you may find other ground covers in nurseries that will survive in your conditions (although you do say you've been fighting this battle for a long time), we gardeners have learned the hard way about alien ground cover species that become invasive over time under ideal conditions.