And since I said " if the weather is nice" I'll expand on that - Prov is windy place and in March/April can be bit cold to NJ people. Also weather changes so just dress in layers for the weather. Don't cross over the I95 through the bridges - nothing to see there really
Providence has some well known theatre life as well if you are into this kind of stuff.
And if you have time go down to Newport, park at visitors center and have a nice walk in historical downtown, again be aware this IS water front so may be breezy (girls tend to hate cold&wind). also too many good places to eat& drink to list them all (Mud tavern is one), Red Parrot is good there are plenty others not any worse but less exposed/crowded. Church where Kennedy wed is just one block up the hill from Red Parrot. I would suggest to do the Cliff Walk but I am not sure it got repaired since Sandy - same goes for Ocean drive (you'd see most of the mantions - this is a car drive).
Plan to spend at least half a day in Newport including travel from Providence. Toll bridge is kind of steep price ($4 each way) but hey Newport is worth it.
Good luck and have fun! Take some pics at the State House
Also check that there are no races in downtown that weekend unless you like crazy runners crowd
( coolrunning.com is a good place for schedules and such)