I live in a county of about half a million folks who are somewhat clustered into 10 named areas, some incorporated, some not. 15 miles or less will get me into 4 of those areas or the 'suburbs' of two more. Primarily we shop chains, whether they are banks, retail, food services or vehicle services. While there is 1 Macy's in my shopping area, there are probably a dozen office supply places that are shopped, and nearly 3 dozen of a grocery store that is shopped with who knows how many gas stations and fast food locations that are shopped. And banks? I can think of a half dozen right off my head that are shopped in my area and each of them has at least 5 branches. Storage units? I am aware of three different companies that shop ones in my area, one of them has two clients with multiple locations.
When I was getting started I carried 4x6 filing cards in the car and when I did a visit to a shopping center or strip mall I did a quick sketch with the street number of the center and the names of the streets adjacent to it. I listed the names of all stores in the shopping center or strip mall. I also marked which exits had traffic lights to get me off the property, if any.
I have another sheet that lists clients and as I discover who is shopping them, I put the company name on that list that is having folks do the jobs.
So when I got a shop at shopping center A, I could look at my card for that location, see the other stores there and check my sheet to see if there were other stores there that were shopped and go to those companies' job boards to see if any work was posted. I could also check the cards for nearby shopping centers and strip malls to see what, if anything might be available.
I haven't needed to do this for some years now because I just know that when I am going to shopping center A, 4 stores there are shopped regularly, and I can check the appropriate job boards to see if there are shops that the timing and rotation will work with the shop I have accepted. By now I have also ingrained what the easiest in and out to the parking lot is (depending on my approach and departure directions). You build routes that way that saves a lot of travel time and gas.