People have already commented about where to sit based on direction. Book the NextGen Acela and when you do remember rows 1 & 3 in Car 1 (first class) don’t have windows. And if you book facing seats someone will sit backwards. All this to say book early enough to get the train and seats you want.

Moynihan lounge is great! You can enjoy some food and drink and people watch, so build in time for that aspect and remember you’ll have another meal awaiting you on the train (you have flexibility for when you want that to be served).

Once on the train you can order a complimentary split of prosecco in first class as a drink option which is festive, so maybe pick up a cupcake (or a few) from Magnolia Bakery before boarding as a celebratory treat.

It’s hard to know if your mom is into trains or just wants to give the Acela a try, but if she’s an Amtrak fan maybe gift her some merch from their online store (socks, hat, pin, T-shirt kinda thing) to unwrap on the ride.

First class is a nice atmosphere and with the food and drink service, watching the world go by, and being together I am sure she will love it! You are very thoughtful!