Getting camping and leisure equipment on the fly is far harder in Italy than the States. Casual camping isn’t as common. Also, renting articles of clothing is uncommon. Italy was poor until 50 years ago. Clothes are private. They belong to you alone. As for your trip, you’ll have the country to yourself if it’s a 20-day trip. Any itinerary works. Como is pleasant, so are all the other lake towns (Garda and Maggiore are also very worthwhile, Maggiore for its green-thumb sprawl). You might want to cross the border into Switzerland to see Lugano.