Most of the eventers in central area of the Delmarva peninsula have their own places and there aren’t any barns that I know of with eventing trainers in Delaware any more.
Glendale in Easton has a modest cross country course.
As far as keeping horses in an area where you can ride as an event horse should be ridden (i.e., dressage, jumping, and conditioning) I made my own acreage into something I could use to ride because there simply isn’t anything except foxhunting in winter where you do get a good bit of good riding over nice territory.
For jumping I haul out or school at home. Along with most of the others in the area, I think. Be sure to friend me on FB or send me a PM so you can be in the loop when we bring in instructors and do clinics.
I’ve brought in people like Caitlin Silliman, and Tim Bourke is also coming regularly to the area. Both Rolex riders with a lot of great things going on and good teachers.