Hi Martha, me again,
As you're not familiar with the area I would advise that you plan a route & itinerary from now so that precious time is not wasted. A good place to start would be GENUKI Sussex pages where you can find background information on the parishes you want to visit.
http://homepages.gold.ac.uk/genuki/SSX/ or do a Google search for information.
Most of the early burials (probably up to about 1850) would be in the parish church. After that
maybe the area had a municipal cemetery where your ancestors were buried, that's why you need to do as much background work as possible.
Don't be too disappointed as most if not all of the earlier burials will have very weathered & unreadable headstones, that is if they are still in situ & have not been moved

Better than (well, easier, as I do like walking around churchyards

)
would be to check parish registers for burials. I can help with Rusper if you like. I note that WARNINGLID is a manor in the parish of Slaugham (I had to look that up

jane