Drive Interlaken , Switzerland to Lake Maggiore, Italy

I'd go the high passes.

To be more specific : I'd go via Grimselpass and Simplon pass. Grimselpass área is an incredible picnic spot.

I vote Grimselpass and then Nufenen pass. My two favourite passes.
Stop at the top of either pass, restaurants in both locations.
That comes out at the top end of Ticino. You then drive south to Locarno, on Lake Maggiore

pam,

Are you renting and returning the car in Switzerland. I assume you're aware of the usual "caveats" regarding driving in Italy?

Yes we are renting a car in Switzerland and returning it in Italy. Has anyone taken the route through Brig? It looks slightly shorter and wondering if it is just as pretty with some nice non-touristy towns to stop for lunch?

You realize you will pay a big international drop charge to rent a car on Switzerland and drop it in Italy. The car has to be transported back to Switzerland and can't be rented in Italy.

But if you go to Locarno, that is in Switzerland and on Lake Maggiore. Then do the Grimmsel Pass route. Brig is nothing special.

Pam,
"Has anyone taken the route through Brig?" - Which route do you mean?
Interaken - Grimsel Pass - Brig - Simplon pass- Stresa.
That is the route ViaMichelin gives as the quickest (click here for route), just over 4 hours driving. That gives you 2 passes, Grimsel and Simplon. The only towns on that route are Brig and Domodossola. Plus other villages along the way, each of which will have a local restaurant.
Swiss passes usually have a restaurant at the top with views. Grimsel Pass definitely does, can't remember about Simplon Pass.
Website: http://www.grimselpass.com/

"we are renting a car in Switzerland and returning it in Italy." - and how much are you paying to return the car in a different country?

Thank you for the help. The Google maps fastest route is 3 hrs 22 mins and goes via Spiez to Ferden to Brig to Domodossola to Stresa, skips the Grimmel Pass. I don't need fast, but I would like a route that is the least touristy I guess, but still pretty.

That route is taking you through the Lötschberg tunnel.
I looked up the route chosen by Google maps. It says "Take the Lötschberg Tunnel train to Ferden"
This is not a road tunnel, it is a rail tunnel. You put your car on a drive-on, drive off train, and remain in your car through the tunnel.
See this video: https://www.youtube.com/watch?v=fkGMN9cg_Kk

That’s incredibly helpful! I had no idea. Thank you very much! Are there any cute villages off the tourist track along the Grimmelpass route then that might have a lunch restaurant?

Do check the timings of the Lötschberg Tunnel trains. You can reserve, or turn up. They are not constant. They are quite expensive.

Speaking of expensive, it is likely to cost a pretty penny to drop a Swiss car is Italy. I hope you have taken that into account.

There is a restaurant at the summit of Simplon Pass. I passed it in April. At that time it was barely open - the drifts were 30 feet high. But the road, although wet, was open.

You don't need it to drive in Switzerland, but Italian law requires an IDP if your driving license is from North America. I see that you have traveled quite a lot and probably know about the IDP requirement, but for those who don't you also need one for Austria and France.

Not a lot in Brig. If you decide to avoid the train and go the low route to Brig along the Rhone valley, you should know that the autobahn along there is tedious and not at all scenic, and much is under construction. You may go 5 km on limited access road, and then back off again for 10 km of single lane construction road, and then back on for a short while, then off onto regular roads again. When I drove it most recently I gave serious thought to using the train to avoid all that the next time.

A few years ago it was much slower but simpler because it was a simple straight single lane road all the way from Brig towards Geneva. It is being "improved".

I expect that you are well acqainted with mountain pass driving, but those who aren't it is important to go down in the same gear that you would go up in. Just don't over-rev the engine, and be sure to rest and cool your brakes. Nothing worse than smelly brakes just before they stop working.

Simplon Pass is very scenic, but not as beautiful as Nufenen or Grimsel. Watch for the speed cameras in Domodossola.

Second vote to return the car in Switzerland.

Very easy to take train from Switzerland to Stresa. You will need to buy Swiss train ticket to Domodossola and Trenitalia ticket from Domo to Stresa. Make sure both are same train so you don’t have to change trains in Domo.

Recommend returning car in Switzerland. If you need a car in Stresa or Italy, there is an Avis rental in Stresa. But if you are using the ferries to sightsee on Lago Maggiore, no need for car.

Ditto comment about drop off fee in different countries. we had a car from Paris to San Sabastian Spain last year and drop off was going to add several hundred dollars -- we dropped on the French side of the border and took a taxi the rest of the way. ditto across Spain to Portugal. drop off was going to cost many hundreds of dollars. we dropped in Spain and continued by train.