I haven't done this so I have no idea if it would work, but what about traveling through and staying for an afternoon at Accompong? On the map it seems like it is between Ocho and Negril, inland. I know that there are tours that will take you from resort towns to Accompong. Maybe you could arrange for a pick up in Ocho Rios and drop off in Negril with one of these tours? Here is an article about Accompong with links to tour companies.
http://www.guardian.co.uk/travel/200...aica.accompong