1, without the email. Tell them before, they become obligated to offer, plan, and you get tired climbing the WP stairs.
Go, do, you need time alone, and when it is too late to do anything else, the night before you leave in the morning, call them, after you eat, shower, nap, and give them your regrets for you would like to see them.
A minor divirsionary attack on the airport, your flight will be cancelled, and you can spend the day with them. If they really want to see you there are always ways.
A four day trip would cause me to need extra sleep. I am sexually excited by strange beds, hotels, I was not a business traveler. It takes a few days till my mind catches up. Oh, just for sleeping.
Air travel tires me, the strip searches, the interrogations, I do look like I am up to something. I always plan for extra rest.
For your own peace of mind, you will not run across anyone you know. It is not like going out for groceries, where neighbors you aviod can start talking in public. It is a little freedom, a place where yes, I am strange, a foreigner. You need that.
The girl thing, I wanted to see you but there was someone at the conferance, and I thought maybe. It did not happen, but a girl's got to try. Everyone understands.