I will be going to Amsterdam this summer for a few days and then down the Rhine on a river cruise. I have not been to Europe since the 90's. I will be flying from Logan to Amsterdam. On the way home from Basel to Amsterdam KML and then Delta to Logan. I am a global entry member and my mother is not. We will have carry on luggage and a personal item. Could someone explain what what to expect (customs, security etc?).
Global Entry only helps when you land at Logan on the way home. It is as easy as it gets. Get off the plane and head toward luggage claim. On the way, you will go through Schengen Immigration and get your passport stamped, maybe a couple of questions (purpose? how long you staying?). You have to go through the luggage carousels area even if you just have carry-ons, walk out the "nothing to declare" door and that is customs. Welcome to the Netherlands.
You can take the train to Amsterdam Centraal, or maybe a bus will get you closer to your hotel.
Coming home, Basel to Amsterdam is just a domestic flight. It will land in the domestic section of the terminal, and your flight to Boston will go out of the international section, so you will go through a passport check between them and get your passport stamped again. Probably some kind of secondary security for a flight to the USA.
When you arrive at Logan for your int'l flight, you will be entitled to be on the faster TSA precheck security line as that is included with Global Entry. Your mother, unless she has TSA precheck, will be on the regular security line so you will need to decide if you want to wait on the regular line with her or wait for her after security.
If you're flying Delta to Amsterdam, you will be going to Terminal A. I've flown to AMS from BOS a few times and Delta uses Airbus 330 aircraft. I find them more comfortable than 767s and I've sat in all 3 ticket classes; I think the A330s are newer.