Heading to or from Maine? most likely you will be taking rt 95 through New Hampshire to get there, and paying a big toll. New Hampshire has the shortest sea coast line of any state (aprox 15 miles) however it also has the best shoreline drive of any of them I've been on. Rt 1A and 1B.
Coming from the south take the first exit after Rt 495 and 95 join in MA, (last exit in MA (59? I think)) follow the signs to rt 286 (second left turn) and follow it to the Beaches. Rt 286 ends on Rt 1A in Salisbury, MA, go north on 1A (left). Right away you will cross into Seabrook, NH (the nuke plant is on your left across the marsh) cross the bridge and you enter Hampton Beach, ticky tacky tourist trap, side show, arcardes, bars, fried dough, and a big beach. be extra carefull trying to park or drive here, NH makes as much in tickets and fines here as the rest of the state. Get past that mess and you get to see the real NH coast. Overbuilt seaside homes give way to cliff side driving with vast ocean views on one side and real mansions on the other. This is the area to get a great picture of your tear with an ocean background!
Once you get up past Rye Harbor you will eventually come to a wooden bridge, not long after that Rt 1B will turn off to the right, follow that to see New Castle, NH with more ocean and marsh views, then views of the Piscatauqua river and across it the Portsmouth Naval Ship yard, with the castle like jail and possibly a sighting of a modern fast attack submarine. (if you want to go on board a real one http://www.ussalbacore.org/
) Rt 1B ends at Rt 1 at the end of the Memorial Bridge in Portsmouth, NH. Cross it to get to Maine and follow the signs back to Rt 95 north or check out the outlet malls in Kittery, ME.
Heading south, get off at the exit for Kittery (last one in Maine) follow the signs to Rt 1 south, (not Rt 1 bypass!) Downtown Portsmouth, NH. As soon as you cross the memorial bridge in NH, hang a sharp right at the end of the guardrail and loop back underneath the bridge to find Rt 1B toward New Castle. When you get to the end of 1B, take a left onto 1A follow it all the way to the MA border, then follow the signs to Rt 286 and Rt 95 south.
Most of Rt 1A has side walks and paths along it. In good weather you will see plenty of bicycle riders in the breakdown lanes, an excellent break from driving, if you can find a good spot to park.