Itinerary and train help

Best routing depends on where you will be in Switzerland before heading south.

A two-country rail pass is extremely unlikely to be a good financial decision, because Italian trains are relatively cheap. It's possible that some sort of Swiss pass will be beneficial, depending on how much traveling you expect to do within Switzerland.

As I understand your question,you have four nights to spend in Italy before heading to the Dolomites. Cinque Terre would be a long journey out of your way so I suggest you stick to the two lakes.

You do have to pass through Milan to travel between them but it is not a problem. Coming from Switzerland, I would use the opportunity to travel over the Bernina Pass to Tirano, transferring there to a train to Varenna. Two nights there, then take the one-hour train ride to Milano Centrale and switch there to a train heading to Stresa.

You would need to return to Milano Centrale to catch a train heading to Bolzano, gateway to the Dolomites. You will change trains once on the way, maybe in Pandova (I did not look this up).

I would definitely not get a two-country pass for this trip. Just buy point-to-point tickets for Italy. You might want some type of Swiss Pass for Switzerland, depending how long you will be there and how many trains and lifts you plan to ride.

Which lake makes more sense depends on where you are going in Switzerland.

Stresa is on the main line Milan - Stresa - Domodossola - Simplon tunnel - Brig. Which then connects to either Geneva or Lötschberg tunnel - Bern or Berner Oberland.
Varenna is on a local line Milan - Lecco - Varenna - Tirano - Bernina Pass - St Moritz - Chur
You can see all this on the rail map here: https://www.sbb.ch/content/dam/infrastruktur/trafimage/karten/karte-sts-pass-gueltigkeit.pdf
The Bernina Pass route is a lot more scenic. It goes OVER the Alps instead of through in a tunnel. But it leaves you at the eastern end of Switzerland.

It all depends on where you want to be in Switzerland, and how many days you have. If you have enough time, you can do a long loop through Switzerland and go out by one route and back by the other.

"My understanding is to get from one lake to the other you have to go to Milan" - by train yes, unless you want to cross both lakes by ferry and connect by buses, which would take a lot longer.

"I'm wondering if it makes sense to get a 2 country rail pass or just buy point to point train tickets?" - a rail pass never makes sense for Italy. Advance purchase tickets are a lot cheaper.
A Swiss Pass or card of some sort may be worth it, it all depends on how many trips you are making in Switzerland.

Thank u so much for the input and the map link - I need to print that one for sure!

To clarify:
July 12 - arrive Zurich 9:15 am - head to Lucerne - Mt Titus and/or cruise on lake
July 13 - mid-late afternoon lv Lucerne and take train to Interlaken and make way to Wengen - plan to arrive early evening
July 14, 15, 16 Wengen
July 17 - leave Switzerland early in the morning for Italy Lakes area - either Como or Maggiore
Arrive Lakes region July 17 early evening
July 17 - July 21 lakes
early July 21 - head to Cinque Terre
July 25 - lv Cinque Terre early and head to Milan for 1 night
July 26 - friend leaves - I head to Dolomites and need to be back to Milan late afternoon July 30th to head home on July 31

Question - The Bernina Express was mentioned as a possible way to get to Italian Lakes. It seems from Wengen area that it would take roughly 4 hours to get to Chur to catch the Bernina and then another 4ish hours to get down into Italy. It seems the cost for Bernina is $160 which for me is quite expensive, but if it is a definite DON'T MISS then I will find a way. I haven't booked any accomodations. # of days in a particular area is somewhat flexible. Since I will be heading into Italy from Wengen/Interlaken area - what is recommended?? Is there a "better" way to rework this in order to catch the Bernina or just plan on Interlaken - Speiz etc??

Thank you!!!!!

The Seat61 website has wonderful information about European trains. There's a whole section on the Bernina Express. Down below the photos there's a section explaining how to score a much, much less expensive ticket on that route. I haven't done that myself (haven't been to Switzerland recently), but it sounds like a great deal.

You do not need to ride the named Bernina Express train. Regular regional trains run frequently on the same tracks, with the same views, and are less expensive.. Our tickets from Pontresina to Varenna a couple of years ago were around 32 CHF, purchased in advance.

July 14, 15, 16 Wengen
July 17 - leave Switzerland early in the morning for Italy Lakes area - either Como or Maggiore
Arrive Lakes region July 17 early evening

Wengen is the Berner Oberland. The direct route from there to Italy is: Wengen - Spiez - Lötschberg tunnel - Brig - Simplon tunnel - Domodossola - Stresa - Milan (see map).
I.e. the obvious place to stay would be Stresa on Lake Maggiore. The Bernina route to Lake Como would be a huge detour, and may require an overnight stop en route.

Thank u everyone for your help :)