I can understand reluctance about feeding reptiles, since this will increase risk of parasites. (However, one can treat internal parasites with medication to manage that risk.)
Would I be happy with ALWAYS just one type of food? Especially frozen, then thawed? Nope. I'd want variety - just like every creature does when they can choose.
Why do you feel that rodents are better food? Aside from the variety issue, some subspecies of Kingsnakes (especially Gray Banded and mountain varieties) usually feed on lizards or snakes, and only occasionally take rodents.
Also, in the wild, snakes will always choose a Pocket Gopher, Deer Mouse, Kangaroo Rat or other rodent over a House Mouse.
Let's keep all this in mind as we feed. Knowing that we would NEVER be happy with just one food type ourselves...