We are going to stay in condo for 4 nights in Varenna at the beginning of July. I would like to spend 1 or 2 days hiking along the shore to enjoy views of the lake. Is any good hiking trails in mid lake area with unobstructed views ?
Is any good place to buy groceries or better to bring everything from Milan?

I bought cheese & meats & fruits & bread & wine in Varenna from small shops but I doubt you will find a supermarket. You can probably find larger stores and supermarkets in Menaggio (reachable by ferry) and Bellano (reachable by ferry and train). Be aware that stores in any of the lake towns will most likely close between 1 & 3pm.

Contact the condo landlord to ask what's available and also ask what's already stocked in the kitchen if you decide to bring groceries from Milan. I've rented places in Italy that had nothing inside the cupboards, not even salt or oil or coffee. Sometimes landlords are willing to shop for you in advance.

There is a shore path in Varenna, but it's not more than a 10 minute walk from end to end as I recall (and quite crowded with visitors during tourist season). If there are other shoreline paths for pedestrians, you will need to take a ferry or train to reach them. I'm not a hiker so can't be sure but have been under the impression that most people hike in the mountains overlooking the lake to get the best views rather than the shoreline. There are cable cars in some towns that can take you to higher paths. Or else people visit the famous gardens for walks. If you don't mind climbing, there is a popular hiking path above Varenna.

Varenna has a small grocer and a deli, which we found plenty for a short stay. And plenty of restaurants/cafes.

Not sure about hiking along the shore near Varenna but there are paths up higher (which are not particularly well sign posted).

This is a great tour, especially for views.

http://www.bellagiolakecomo.com/bell...belloni-garden

There's also a fort above Varenna, which will lead to great views, though it's obviously more strenuous than walking along the shore.

You can also get a workout hiking to and from Villa Balbinello.

And for hardcore hikers, there are all kinds of hiking trails from and above Mennagio. You can find maps at the Mennagio Tourism site or Google something like Mennagio hiking trails.

One thing you learn from the Villa Serbelloni park tour is that a lot of plants and fauna around the Lake were imported from all over the world, resulting in the beautiful variety of plants, flowers, etc.

However, if you have hay fever, it's really brutal to stay there in spring, around May. I experienced it firsthand. And I would take nearby day trips to Bergamo and Lugano, where I'd be okay. But as soon as I returned to the mid-lake area, it would hit me again.

From Varenna main square, where there is a small grocery shop for limited supplies, you have three walking options: uphill to Vezio Castle or either south on Sentiero del Viandante to Fiumelatte (short) or north to Bellano (train back).
Another walking option is the Greenway walk from Collonno to Griante, on the far side of the lake. You can pick up the walk by taking the ferry to Sala Comacina and there are two interesting sites to visit along the route - Villa Balbianello and Villa Carlotta. We actually terminated our walk at Villa Carlotta, as the ferry stops there to return you to Varenna.

There are tons of hiking trails in the Lake Como area. Habve a look at a map like Kompass, http://www.pcn.minambiente.it/viewer/ or http://map.geo.admin.ch/?lang=en
The panoramic trail I like best goes from Menaggio Croce to Monti di Tremezzo and then via Calbiga - Monti di Lenno - Cima della Duaria to San Fedele d'Intelvi (day 1) and then via Orimento - Sasso Gordona - Monte San Bernardo - Monte Bisbino - to Sagno bus stop (day 2).

Bellagio has a small grocery store at the top of the town. When we first visited it would close mid afternoon but not so on our last visit there.

Thank you very much everybody, very useful information!

scrb11 mentioned a "fort" in the hills above Varenna. the Castello di Vezio is somewhat interesting, but the views are spectacular and the on-site falconry is fascinating if you time your visit to the release of the birds. Depending on the route taken, the walk up to the castle can be strenuous.

http://www.varennaturismo.com/en/por...ello-di-vezio/

http://www.eccolecco.it/en/art-and-c...stle-of-vezio/ [Play the video.]

Double-check the open times as they seem to change every time we visit.

We've done this 'hike' from Griante on the western shore. We ferried to Cadenabbia and walked to Griante.

http://www.griante.com/index_en.php?page=sanmartino