I agree 100% with Abinoone regarding both wolves and the elk population in both Yellowstone and Grand Teton NPs. I live in Gardiner, MT, which is within walking distance of the North Entrance, and I'm in the park photographing the animals 4-5 days a week. I can tell you elk are numerous both inside and outside the parks. Wolves serve a very important purpose and their reintroduction in 1994 and 95 has done much to restore the ecological balance to the ecosystem, as Abinoone has said. According to the 2023 edition of the Yellowstone Resources and Issues Handbook, published by the National Park Service, "Yellowstone provides summer range for an estimated 10,000 to 20,000 elk from six to seven herds, most of which winter at lower elevations outside the park." Additionally, that same guide states that "[E]lk are the most abundant large mammal found in Yellowstone." The loss of elk population was primarily the doing of humans when it was decided that the elk population was so large that the herds had to be "culled" (read, "killed"), which ended in the 60s, but today Montana still permits limited and controlled hunts of Elk outside the park. There is no doubt that the wolves hunt elk but the elk population is today stable or even possibly increasing, according to the guidebook. Don't mean to hijack the thread, but this is an issue raised here and is a matter of significant concern in Yellowstone.
As for the availability of elk to photograph on the east coast, again, as Abinoone has said, there are herds in central Pennsylvania outside Benezette and also in North Carolina just outside Cherokee at the Oconaluftee Visitor Center and also in the Cataloochee Valley of North Carolina.