Sicily

I don't know why RS doesn't have more info on Sicily, but it's one of my favorite destinations. I spent 3 weeks there last July. How much time do you have? If a week or less, I suggest picking one area (perhaps the northern coast, or the western part of the island) - this will make traveling easier. Sicily is big, and there are fewer fast trains there than on the mainland. Some of my favorites: Palermo with a side trip to Monreale, a longer side trip to Trapani/Erice (a lovely small medieval town on the top of a mountain), the ruins of Segesta (Greek temple and theatre), Cefalu for its beautiful cathedral and the rock right behind it (also several beaches). Other areas: Agrigento, Siracusa, Taormina, the Roman Villa near Piazza Armerina. You can get to Sicily by train or bus from Salerno, or you can fly from Naples (I don't know if you can fly from Salerno).

can we rent a car in Sicily and would that be the best wat to get around? We were thinking of maybe 5 or 6 days there.

RS has a 10 day tour of Sicily listed under his 2012 tour list. Perhaps if you went to that site you could see where his tour goes and check out its daily itinerary for more information.
Lonely Planet does have a Sicily guide book available thru the RS web site.

Sure, you can rent one in Sicily. I would say it's the best way to get around. Wouldn't suggest trying to drive in Palermo or Catania. Didn't find any other areas to be too bad though.

Take the Caronte & Tourist ferry from Salerno to Messina. Stay in Taormina and Siracusa with so few nights.

If you Google "rick steves helpline salerno sicily" it finds hundred of postings addressing the various plane train automobile and boat solutions. If you are on a strict Rick Diet you can watch all of his Sicily tv episodes for free on YouTube and then go to those places - whick look good. If you'd like to supplement the Rick Diet there a plenty of guide books that cover Sicily - which is a large and varied place.