I lived in Newport from 1998-2002 while in college at Salve Regina. The first two years I spent living and working on campus, but my last two were all spent living in a beautiful house, and working, in the city. While I wasn't able to experience all Newport has to offer even in four years, I did pick up some tips that might be helpful. Someone emailed me this week asking for some suggestions, where they should stay, where to eat, if they should rent a car, etc. Here's what I had to say:
There are lots of activities though out the year, so depending on when you're going there might be something fun going on. You might want to rent a car if you really plan on seeing a lot of Newport (although it's totally not necessary if you're ok with staying in the 'downtown' area. That's all easily walkable), especially a few of the nicer nature views that are off the main road. However, I'm not sure how you would do that in Newport, as I've either walked everywhere or had my own car while living there.
As far as what to do, of course you should visit the mansions. This link http://www.newportmansions.org/page3569.cfm will take you to a page that can give you detailed information about visiting the mansions, including pricing and packages. The only one that I would visit that is not part of this group is Astor's Beechwood. At the Astor's they do a "living history" tour, meaning actors pretend to be people from the past who actually lived in the mansion and give you a tour as if they were showing friends their house. It's a very fun and interesting way to visit. Their web site is here http://www.astorsbeechwood.com. Almost all of the mansions are on Bellevue Ave, where you can also find the Tennis Hall of Fame http://www.tennisfame.com/. That is another place worth visiting. It's filled with lots of interesting history, and some things not related to tennis as well. The restaurant next door is great too.
Another place to visit would be Thames St. That's where all the shops and some great restaurants are, as well as some of the hotels. It's easily walking distance from the bus station. One of the great restaurants in that area is Brick Alley pub, which is on Upper Thames. Also, Shells and Scales, The Red Parrot and the Back Pearl, which are on Lower Thames, are fantastic. Just remember that these places are very touristy and will be expensive. Some other places (and you can look online for address and directions) that are worth trying are Via Via Pizza (seriously, the best pizza anywhere), Buskers or O'Briens (Irish pubs), Salvation Cafe (Thai food), Coddington Brewery (In Middletown, but really good steak and not very expensive), Patrick's Pub (SO amazing, it's in the basement of a very fancy restaurant, The White Horse Tavern, and they serve the same food, just less fancy and cheaper. I used to love going there on Fridays with my girlfriends), Sardella's (Italian food. The Mayor of Newport opened this place a few years ago).....
Another great area to visit in Newport is Brenton Point and Ocean Drive. Ocean Drive is off of Bellevue Ave, the main row of old historical mansions. The difference is that Ocean Dr contains mansions that people still live in. It's a fantastic drive along the beach, and about half way though is Brenton State Park. One side of the park is rolling fields and pathways (which lead to a huge lookout tower that you can climb), the other side is the ocean and rocks for climbing. It's one of my favorite places to walk around and have a picnic lunch. In the same area you'll find Fort Adams. It's a very interesting place, we took our daughter this summer and did the walking tour. It was an hour long leisurely stroll through the grounds, and at one point under the grounds (I skipped that part). Even at two years old my daughter seemed to enjoy it. There was a lot of room for her to run around...
If you're interested in visiting the beach Eastons Beach and 1st Beach are not too far from Bellevue Ave.
Salve Regina University is off of Bellevue Ave. I think it's worth taking a drive through the area at least to see the beautiful mansions that the University uses as dorms and classrooms.
As far as staying overnight, The Viking Hotel http://www.hotelviking.com/ is so incredibly beautiful, but it's also expensive. My cousin had his wedding there, and the rooms, the food..everything was perfect. It's close to Bellevue Ave and Thames St. Castle Hill (which is on Ocean Drive http://www.castlehillinn.com/) is another amazing place to stay. I almost had my wedding there. I've heard the Newport Hyatt Regency is nice http://newport.hyatt.com/hyatt/hotels/index.jsp. The Newport Marriott was built while I was in school. It's very popular, and a lot of the parents stayed there at graduation http://www.marriott.com/hotels/travel/pvdlw-newport-marriott/. Finally, my husband and I always stay at the Middletown Howard Johnson's when we go to Newport. It's close to Thames St (driving distance), and is a lot cheaper than staying at a hotel in Newport. It has a nice indoor pool and is always clean. It's not fancy, but when we go we're just looking for a place to sleep, nothing too special.
For more information check out this page: http://www.gonewport.com/ ; you'll find a ton of information about places to go, where to eat, where to stay, and activities that are going on.
I've seen and done so much in Newport that it's hard to remember everything. If you have a question, feel free to message me!