In my limited experience, these count down meetings were very professional, very focused, and mercifully short. Issues raised would be dealt with and the various teams would go off to do whatever they needed (or wanted) to do.
For the political people that normally included dinner at a restaurant someone on the team had previously been to.
It was not unusual for someone, in the course of conversation with the waiter, to mention that we were the advance team for the President, Vice President (or whomever) which would lead to the restaurant owner or manager coming out to chat with us and comping (not making us pay for) the meal.
It was a Secret Service Agent to told me that the proper etiquette was to ask the waiter to estimate what the meal would have cost and to leave a tip above what would have been appropriate to that cost. The waiter worked just as hard for a free meal as he or she would have for a fully-paid-for meal.
The lead political advance person and the lead Secret Service Agent will typically be in more-or-less constant contact with one another. The Secret Service is responsible for the safety of their protectee, and the political person is responsible for making sure the trip accomplishes what it is supposed to accomplish.
Here's a real life example:
During the 1988 campaign (George H.W. Bush and Dan Quayle v Michael Dukakis and Lloyd Bentsen) I was travelling with Marilyn Quayle's tour.
There came a time in California when we were asked to have her come to a hotel in Los Angeles to address a volunteer event at which Jeb Bush would be speaking.
My partner-in-crime, Mary Cochran, and I went to the Secret Service Agent in charge and told him what we wanted to do.
A short time later, he came back and said he was very uncomfortable about sending Mrs. Quayle to that event because at that same hotel, at the same time, was a meeting of California narcotics officers.
I asked what the problem was.
The Agent said, "cops with booze and guns."
We really wanted to do this event, so in the end we did it, but only after the Service had advanced a route into and out of the hotel that had the least chance of Mrs. Quayle and the California Narcs intercepting one another.
This is an election year so the Columbian trip will be in the news all the way to November, but my experience with both the Secret Service and political advance teams was nothing but positive.