I fish the Kennebec River every summer. I usually fish by the Fort at the mouth of the river. I fish with eels, big sluggos, bucktails tipped w/fin-s, and mackeral colored plugs. For eels I use a fish finder rig. I tie a 24-28" leader to a black barrel swivel. The other end gets a 2/0 black, short shanked tuna type hook. I thread a 1.5-2 oz egg sinker above the barrel swivel. Make sure you remove any burrs or sharp edges left by the sinker mold from the holes in the sinker before threading your line. I use a heavy action 9' stick with a Daiwa sealine 30H reel and let the eel swim around the rocks at the rivers edge withg thje reel in free spool. Give the bass time to get the bait in his mouth. I also bring along a 7.5'popping rod to throw plugs and jigs. I try to fish a rising tide, right at the fort near the mouth of the river. Make sure you have corkers or other suitable footwear as the rocks can be very slippery. I have also had luck at Popham beach with eels, artificials and mackeral chunks. You also might consider fishing with one of the many guides in the area from a boat. I have had some great experiences out ther during the day when the bugs aren't so thick and the scenery is out of this world. Seals, eagles, osprey etc.
Good Luck and Tight Lines!