It is a really long way from Como by public transport, but if you love mountains, it is a great choice.
Mount Resegone (famous for its “saw” shape) offers one of the best 360° viewpoint of the Pre-Alps (the beginning of the Alps). Over Lake of Como (Lecco side), close to Grigna and with a view over Pianura Padana and Milan. There are different trails to go up hiking, so you can decide which one to follow according to your skills and experience.
To save time, take the cableway at Piani d’Ernia and start your trekking from there. Going up and down could take from 3 to 6/7 hours.
How to go to Mount Resegone:
Take an early bus from Como to Lecco FS (bus C40). Take bus n.5 in Lecco to Piani d’Ernia. Take the Cableway.