Spent much of my working life driving artics in Italy. The best advice I can give you is think safety first where parking. There are Aires in Italy, but these are much much bigger than the French ones, yet very often deserted except for the nefarious types. Avoid like the plague at night. Make sure you know where the full service stations are and head for those. Dont just park up at the side of the road either. There are a lot of horror stories from Italy, many of them are true.
The standard of driving, every Italian will tell you is tip top. Erm, no it isnt, it varies from manic to suicidal, especially in the larger towns and cities. Always carry an Italian phone card, mobiles can be sketchy and many public phones dont accept cash. Depending on the time of year, its Mozzie country, be prepared, they can be voracious. Most Motorways are toll motorways, but not overly expensive and worth using, but you wont see much of the country. Check your tyres regularly for heat, the temperatures can be high in summer, especially inland and that and the state of Italian roads can lead to a number of tyre issues. What else, oh yeah, Grappa is disgusting and the local brews often taste like diesel.
If walking about at night, be aware of where you are going, stay around crowds and watch out for the legions of pick pockets. They go for tourists as a matter of course. Actually eating out is quite reasonable, try to find where the locals eat rather than tourists. Spirits too are not too dear, but beer can be very expensive. Back in my days out there, there were a rash of Irish bars cropping up in towns, they were incredibly popular with Italians and the only places you could get a beer that didnt resemble a knickerbocker glory. Indeed we carried Guinness as a regular load.
Keep plenty of water to hand and a pack of Immodium in your kit bag is worth carrying. As is a 12v plugin mozzie burner.
One of the best tips I can give a newbie to Italy is look at your route, and learn the Italian names of the major towns you will need to look for along your route on signs. As an example Florence is Firenze(catches a lot out) and there are many like that.
As for the local police, those with a white stripe are pretty much comic opera and coffee money(small bribe) is the order of the day. If you run into any problems with a red stripe, pray. Caribinieri are not the friendliest characters on earth and all were born dour and humourless. They will not give you the benefit of the doubt, nor a second chance. Do NOT offer them coffee money
All that said, if you have your wits about you and think safety first, Italy is still and wonderfull country and the Italians probably my favourite Europeans. For the most part they have a real warmth about them.