Hi, the usual route is through the san gottardo tunnel, maps will give you that, but you can take the pass road too and doesn't take much longer, but there are roadworks with alternate traffic between Gòˆschenen and Andermatt, that can mean long waiting time, so i don't think it's a good idea.
The traffic jams are bad in the summer (till half september). There are northern swiss ferien late september so it's still possible i guess.
Check this site some days before http://www.tcs.ch/de/auto-mobilitaet.../prognosen.php and most importantly listen to TP on the radio SRF1. Gottardtunnel is closed for works between 19:30-05:00 except weekends, just so you know.
Even if you have to wait half an hour at the tunnel it's still faster than the classic winter alternative San Bernardino, from luzern at least. If there's the sun, have time and enjoy driving the passes Oberalp-Lucomagno or Furka-Nufenen are a nice touristic alternative.
Alternatively take the train. There are frequent journeys, some of which are direct. It is 2.5 hours. There is a special offer for day tickets at the moment too.
I would expect at least 1 hour delay each way. The old holiday season running from April to early September is now March until October. Saturday is changeover day so heavy in both directions - Sunday should be lighter southbound but is still heavy northbound.
Google maps also has a real-time traffic update, so before you go just check the app and it will give you the quickest alternatives. If it gets red before the tunnel better avoid it, since by the time you'll get there it will just get worse - but I guess Lucerne is not that far...
I did San Bernandino coming back from Milan last September as the signs in Bellinzona gave a 3h wait on the south entry. Nice route and probably worth it for Zurich, but I wouldn't do it again unless I was up for driving.
Just be prepared to wait some time in the queue and plan for snacks and/or good company that you can have a chat with
As has been said by someone else, there are roadworks between Goschenen and Andermatt. Only one lane is open. Depending on the time and which direction you are going, there is every possibility of longer delays there than the tunnel. You need to check the situation on your approach. Here is good for that. http://www.tcs.ch/de/auto-mobilitaet...uelle-lage.php
We exited the A2 at Watson & went into Andermatt for a quick nosey then on up to Hospenthal and Airolo.
A really nice trip and there was one Road works where we waited 2 minutes or so. Appreciate it could have been much worse because it was indeed an alternate traffic set up.