Fly the Gap???

It was a beautiful weekend to fly this past Saturday and Sunday. I got a chance to go flying Saturday on a route up to Placerville, Auburn (stop for fuel - human and plane), Cameron Park then a stop at Stockton before returning to San Carlos. I was flying with my friend Michael and his Mom's friend Mort. We had flight following for the flight and was handed off to San Carlos just prior to Coyote Hills. San Carlos tower frequency seemed to be busy but I was able to report in and was told to report the cement plant for left traffic for runway 12. I continued on in and reported over the cement plant and was told #3 following Cessna on crosswind. I didn't immediately see it but picked the traffic up as it turned downwind. All seemed normal. I had noted that the number of planes calling into SQL started to increase. A plane from Crystal springs, another plane from Coyote Hills and yet another plane. The controller was also dealing with one plane that he didn't have the current tail numbers and was trying to get the pilot to read back the full call sign. The level of tension in the controller's voice was increasing. The controller also started issuing instructions for full stop landings which they seem to only do once they get a bit saturated. The plane coming in from Coyote hills for some reason was maneuvering over the cement plant and said they were doing that for spacing. All of a sudden the controller instructed that plan to leave the air space and fly the "gap". I have heard many calls including calls to remain clear of San Carlos airspace but I have never heard an instruction to "fly the gap". After a few more calls the controller explained to fly the gap between San Carlos and Palo Alto class D airspace... now if you have a nice moving map that isn't that hard to do but can you imagine trying to do that on command with just a VFR chart and at probably 800 feet altitude where landmarks aren't all that visible? Lucky for me the only thing happened on my landing was the controller got mixed up and while I was #1 on short final he said I was #2 following the Cessna on short final. Before I had a chance to reply he caught himself and all was good.

Well know I know what this controller means when he says "fly the gap".