I've been raising pumpkins for over 40 years, I have never had any luck with traveling gun or overhead sprinklers.   pumpkins are finicky, disease travels fast with wet leaves.   There is a farm nearby that raises strawberrys with emitters then when that crop is done they transplant pumpkins and that works decent.   Most of the time its either a pumpkin year or it is'nt.  Its a hard battle when its not meant to be.   I've seen great pumpkins on drier years and they somehow manage drought pretty decent.