Fruit trees definitely need pollinators.
Pollinators are the insects - bees, etc., which carry pollen from flower to flower and pollenate the pistillate portions of the flowers, resulting in fertilization of the ovary and development of the fruit. So...you can see that a pollinator has to be VERY close!

But, pollenizers, the plants which would flower concurrently with your existing trees, and serve as a source of pollen for cross-pollenization, only have to be within reasonable flying distance for the local pollinators.
Most peaches are self-fertile; though I can't speak for Frost, specifically. Plums typically need a second compatible variety to serve as a pollenizer.