I've been away from Wexford for a long time now so I'm probably not the best source of advice. Duncannon I would describe as 'back end of nowhere', never liked the place (losing to them in an under 14 cup semi final replay out there probably the main reason). They seem to be doing very well in recent years and I know they have a guy called 'Carlos' playing for them, who played with Sligo in the Eircom league and had trials with Wexford Youths, he's on the Oscar Traynor team too.
Forth are a bit closer to Wexford town, another rural club, haven't a clue what facilities are like these days. Again they seem to be doing pretty well and have at least one player on the Oscar Traynor side this year. One thing both sides will guarantee is a big physical presence.