(As a local, though, my friends and I always wish that there were more bars in Trolley Square and in Wilmington in general. There are about 7 bars there, which is nice. Wilmington's bar area is Trolley Square, centered around the intersection of DuPont Street & Delaware Avenue. I don't think I've ever seen a young gay man or woman in Rehoboth, which I guess is the age you think of first when thinking of gay places. Rehoboth Beach has a different feel than a normal gay area from my experience, the gays all tend to be in their 40s, 50s, and 60s. I don't know how old you are, but Rehoboth Beach might be nice for you as well. It's actually called "Midtown Village", but Philadelphia area residents despise the name as a "manhattanization of Philadelphia". Philadelphia's gay neighborhood, from what I understand, is B3, located at around 13th & Sansom Streets. If you want gay culture and whatnot, you'll have to find it in Rehoboth Beach or Philadelphia. (Most people here think of the entire state of Delaware as a "metro area".) The gays that I know from work or friends' workplaces actually all live out in suburban areas I know a couple lesbians that live in your typical townhouse in suburban Middletown, I know of a gay guy that lives in Brandywine Hundred (suburban area north and northeast of Wilmington), and another gay guy living in the Stanton area.
Wilmington's gay "neighborhood" is Rehoboth Beach down at the beach. As far as gay areas in Wilmington, there are none.