You can go outbound, but not inbound.
This sucks for anybody who likes riding bikes north, or at least coming home from
Inbound detour cuts you through sharpsburg, putting you onto the highland park bridge.
If you fear the Highland park bridge, or are headed towards town and not away, you can take “friday road” (stay on main st through etna, then fork right with parker and immediately fork left on washington or friday) UP over the hill into milvalle, which will let you access the 40th st bridge or the bike trail.
Or I guess you could just take the unfinished trail down to 40th st