Trenord not purchasable, less than 3 weeks out?

It looks to me that the problem could be in the combination ticket of different operators.

Trainline is a reseller and I would check with the people running the services. If you try on sbb.ch, it looks they will sell the ticket. If you look on trenord.it, they will sell Lugano to Gallarate and Gallarate to Casorate Sempione, but not the through ticket for both services.

It says it operates a service in first and second class that is not bookable (non prenotabile). Trenord operates only Regional and Suburban trains. You don’t need to worry about the seats being sold out. Those types of trains are like subways. Seats are not reserved, they are on a first come first served basis. In the very unlikely event the trains are so full that no seats are left, you simply stand up until a seat frees up, but you can still get on board. Actually purchasing those tickets ahead of time for those types of trains is totally unnecessary. Just buy the ticket when you get to the Lugano station.

As lachera says, you can book Lugano to Gallarate online with Trenord, or I can see it on SBB. This is where you change to the spur line to Casorate Sempione. Or you can wait to the day of travel and buy tickets then, as Roberto suggests.

Or, since this is an airport hotel for the night before your flight home, you could change to something closer to MXP with a shuttle.

Trenord is a commuter railway. There is no need, and no advantage purchasing tickets in advance. Forget about trainline. This is like trying to buy a NY Subway ticket on Expedia.

Just buy the ticket at the station in Lugano. Or if you want you can also buy it in SBB. Buying it at the station gives you a traditional paper ticket, whereas getting a digital ticket may be complicated if you do not have mobile internet.

Lugano to Gallarate will be on a TILO train btw. Tilo is a joint venture between Trenord and SBB, and runs the cross border part of the Greater Milan commuter train network.

Brilliant, what a relief! Thank you all so much. I suspected the combination of "main and spur" might be the issue, but I wasn't sure how to confirm. I feel silly that it didn't occur to me to search the legs separately, so I suppose I can just plead exhaustion and repeat how much I appreciate you all clearing it up for me.

Roberto and WengenK, I particularly appreciate the confirmation that these trains don't need to be bought in advance. I suspected as much but, given they are tied to our last night pre-flight, wanted to be certain. Thrilled to know it's simple to handle day-of! We were less concerned with purchasing and more with knowing how often, and where, the route ran so we could loosely plan our day.

Appreciate the tip, Lola -- we chose the Osteria della Pista in Sempione for our last night particularly because it has a 10-minute shuttle to the airport. It gave us a little distance from Malpensa itself, has a great vibe and lovely-looking restaurant, and I think I recall that my husband had located a small castle nearby.

Our plans for 3 July are wide open, so if anyone has especially favorite adventures on this route between Lugano and Gallarate/Sempione, we're open to suggestion!

That looks like a nice little hotel—-I like the equine theme! We need a hotel near Malpensa for one night in September; I might book there. It would be easiest for us to just go to MXP from Milano Centrale and have their shuttle pick us up. I will look into this.