This a an urban cache, with the potential for TONS of muggle activity. As such, before or after business hours wil be your best time to go after this cache. Otherwise, you will probably need to have an activity planned for what you appear to be doing, when in fact you are searching for the cache. Pretending to talk on your phone while leaning on the wall might be a good possibility.
You are looking for a..... container that is appropriate for the location. Good Luck!