Thank you for your question.
3 areas are accessible to Regional Rail in Delaware. Claymont, Wilmington Train Station, Fairplay near Delaware Park and Newark just south of University of Delaware. However there is some limited service to all the Delaware stations so the Marcus Hook station just north of the Delaware / Pennsylvania line is a popular station since it has later or extended service times available. North Wilmington / Claymont have a variety of apartment options available. Dover is about hour and half south of the Delaware / Pennsylvania line and there is a Dart (Delaware transit bus) that runs from Wilmington to Dover.
If you want to discuss further, please contact me at 302-981-6485.