Well, the impeachment process had cleared the House Judiciary Committee by the end of July. The next step would have been a vote by the full House followed by a trial in the Senate. It's very possible that the process would have played out to its conclusion by October, culminating in Nixon's removal from office and Ford's succession. Had Nixon been convicted in the Senate, it becomes less likely that Ford would have pardoned him, which would mean that Nixon could well have been put on trial in criminal proceedings in 1975. If Nixon were removed from office, I would expect that Republicans would have done even worse in the midterms, though you could argue that a few GOP House members and Senators might have saved their own skins by voting for impeachment or removal as the case may be.
It's worth remembering that none of this is particularly likely; what precipitated Nixon's resignation was a delegation from the Senate paying a call on the White House to tell Nixon that he likely didn't have the votes in the Senate to avoid conviction and removal.