Although you said it has been cleared up for you, I'd like to add my experience.
I was fortunate enough (I think) to fly the editor of the
Waterway Guide on a photo mission from Manteo, NC all the way down to Fernandina Beach, FL to shoot photos of just about every marina along the Intracoastal Waterway. Cities that we overflew included Wilmington, Myrtle Beach, Charleston, Hilton Head (who knew I'd end up living there 6 months later) and Savannah. I've since done some work up near Patuxent River NAS and Norfolk. The point being, I was flying circles between 800 and 1000 feet in some busy airspace. I made every attempt to stay on flight following the whole way, but there were times when I was outside or below radio or radar range. During those times, we just cruised about minding our own business. However, when we approached controlled airspace, the magic words were "XXX Approach, Skylane 36AF, VFR request". I guess when ATC hears that, they expect you to tie up a decent amount of time on the frequency, so they take care of the critical business before they get back to you. When they finally asked what we needed, we'd give them a detailed, but brief, run-down on what we were doing. "36AF is on a photo mission along the Intracoastal waterway, southbound below 1,500, would like traffic advisories and Class C transition (if applicable)." If they asked for more information, we would give it to them. On a couple of occasions when operating inland on the Savannah River and near Wilmington, they would have us report "on station" and again when ready to proceed to the next location.
The only problem I ran into is when operating within a mile of Wilmington's active and the editor didn't exactly know where the marinas were that he wanted to shoot. Trying to tell the tower controller that we really didn't have any idea where we needed to go next didn't go over too well. Moral of this story: make sure you know where the photo location is prior to taking off. Giving the controller references to prominent physical landmarks or a radial/DME off a VOR is your best bet.
Just remember, you can never give them too much information. Just make sure they solicit that information, so that you're not tying up the frequency.