What better way to visit than walking with an expert guide and hiker?! David Morton organizes trips from 5 to 8 days, usually tailor made to your requirements (for up to around 6 people). Expect to walk for about 5 to 9 miles a day (3-5 hours). You will encounter many panoramic spots and Roman ruins, enjoy woodlands, scenery, ancient history and also great food. You meet in Rome (maybe you'd like to have a couple of days here first) and everything else is organized for you and included in the price, with the exception of traveling to reach Rome. He has various itineraries but you can see in the map below the Castelli Romani/Alban Hills one, which reaches Frascati. He recommends spring and early autumn as the best times for trekking. David has personally selected B&Bs, historic monasteries and village inns that offer great comfort and delightful old-world ambience. Budget or upscale options are available in many locations. He adds a newsletter to his website with pre-organized trips if you don't wish to take a customized tour. You can contact, discuss and book through the contact form on his site here.