We are visiting Northern Italy in the middle of May. We have 3 nights and the better part of 3 days for our visit. (We will return to Milan in the evening of our last day.) Our lodging is at an Airbnb in Como and we will using our feet and public transportation to get around. It looks like a HOHO Day Pass with the ferry will be a good way to see other villages on the lake. How would you recommend spending our days? I have read and watched a video or two about Bellagio and Varenna. What suggestions do you have?

Current ferry schedule goes until May 27. That will dictate a lot of what you do, when you go, etc.

Do you just want to wander from town to town, or do you have specific things you want to see and do? If you have a list, you need to study the ferry and bus timetables and develop a plan for each day. Figure out which ferry stop, decide when you want to arrive and depart each sight, where you'll head to next, etc. Definitely know the time of the last ferry or bus back to Como.

Lake: navlaghi.it
Bus around the Lake: asfautolinee.it/it/orari-rete-extraurbana
Best viewpoints around the Lake:
montegeneroso.ch/en/monte-generoso/history
aapigra.it/aap/funivia
funicolarecomo.it
Unesco world heritage sites:
ticino.ch/en/explore/unesco-world-heritage.html