For seeds requiring stratification, there probably is no easier way. Thinking in terms of pre-domestication, beach plums are the kind of fruits that would have been eaten by large mammals, who swallow pits whole. When I worked for the Forest Service, I used to find coyote scats made entirely of wild plum pits. The passage through the mammal's digestive tract erodes the thick shell of the pit, allowing moisture in for germination; and the exposure to cold corresponds to the pit lying dormant through the winter to germinate in spring.
The beach plums I have seen were planted as a hedge along a path, and grew as dense, tall shrubs.
I just planted some last week. They aren’t very big seeds. I think a winter in the ground will probably work. I’m just guessing though. It works for peach pits. These are a couple years old. Not sure if that will help or hurt.
We grow beach plums in Minnesota - zone 4a sand plains. In our climate they look and taste similar to our wild american plums - but....they are WAY smaller. Short little babies. Our American plums can get up to 15 feet tall - most being around 10ft. The beach plums seems to top out at 3 feet or so.
Jason Hernandez is correct - coyote (and bear) scat is loaded with wild plum seeds. I have not seen them "digested" or otherwise opened in the scat, but they do come out whole. In our experience, it can take cold 2 seasons (cold/hot/cold) for a plum seed to germinate, but we do not open the pits to free the seeds.
All of these native plums are worth growing. They are cold hardy, drought tolerant, and tasty.