It’s better to have them meet you in your lobby or even in your room than to meet in the park somewhere.
You shouldn’t need to call ahead to the gatehouse.
I’ve had visitors drop by, even when staying at Contemporary. All that happens is that you tell the guard you’re visiting “X” family and give their room number. You’ll then be directed to either park, or to go to the valet if there is one; the choice is yours whether to self park or not.