If you're looking for a meeting place or a good stop around ½ or halfway between Guilford and Newark, you can try Stamford, CT, which is almost an hour west of Guilford, or about 1 hour northeast of Newark.
About ¼ or a fourth of the way, you can stop at Bridgeport, CT. This is about half an hour west of Guilford.
About ¾ or three fourths of the way, you can stop at Yonkers, NY. This is about 1½ hours west of Guilford, or about half an hour northeast of Newark.
If you drive straight through without stopping at all, the total distance is 105 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, 59 minutes.