If you're looking for a meeting place or a good stop around ½ or halfway between Newport, RI and Boston, you can try Taunton, MA, which is almost an hour north of Newport, RI, or almost an hour south of Boston.
Other possible places to stop near the midpoint include Raynham, and Scotland Estates.
About ¼ or a fourth of the way, you can stop at Fall River, MA. This is about half an hour northeast of Newport, RI.
About ⅓ or a third of the way, you can stop at Somerset, MA. This is about half an hour northeast of Newport, RI.
About ⅔ or two thirds of the way, you can stop at Brockton, MA. This is almost an hour north of Newport, RI, or about half an hour south of Boston.
About ¾ or three fourths of the way, you can stop at Randolph, MA. This is about 1 hour north of Newport, RI, or about half an hour south of Boston.
If you drive straight through without stopping at all, the total distance is 71 miles. The distances shown above don't include local roads to get into each town, so if you're planning a long road trip, make sure you factor in traffic and road conditions, rest stop breaks, and interesting detours along the way. If you're in a rush, you can do the trip with zero stops, and your total travel time would be around 1 hour, 27 minutes.