Killens is probably your best bet. We go to Dover on occasion and have taken advantage of parking at the Casino, which is a dirt lot with no hookups. Not the most comfortable for an over nighter. Killens is nice, with water and electric hookups. The dump station area is tight, but I think they are making it more user friendly.
My x and i stayed at Killins Pond and it was very nice. It snowed the day we were there and there was only one other camper in the whole park..Lots of trees to dodge in the park..The county fair grounds had water and elec hookups...but nothing else...
2003 Four Winds Infinity 37'
2011 Lance 855
3.5# Minpin named Darcy
Ford F250 Super Duty