Would love to catch them consistently on Lanier. Fish for and catch crappie every week and have never caught more than a half dozen total pperch on Lanier and don't know of anyone who specifically targets them. Hope you can share some good information because yellow perch are fine eating.
From the dam down to the Stevens Creek Dam there is plenty of water to run just about any size boat. There is a boat ramp below the dam on the Georgia side and one on the SC side just downstream from HWY 28. There is also one on the Georgia side in Evans in Betty's branch but getting to and from the river can be shallow at times...perfect for small boats and kayaks and I have seen sizeable center consoles launched there but depending on the water levels it can be more difficult. The ramp below the dam is about as good as they get. There are a lot of kayaks used in the area also....I am apt to falling off anything less than 60 inches wide so I don't have one but there are a lot of them used there. There is also some good bank access just below the dam on both sides of the river and lots of racoon bream caught off the bank with minnows, worms and crappie jigs.
Fish are apt to be anywhere but we usually just work the bank with crappie jigs (1/8th to 1/16th ounce curly tail grubs) and try to keep them close to the bottom, just above the grass. Cover or bare banks....it makes no difference, they will be everywhere. I like yellows and oranges/browns but have caught them on just about every color imaginable....I just like yellows and orange/browns. Some folks will tip them with a crappie minnow and do well but I don't bother with them. Nightcrawlers and pink worms will also work. Very simple fishing, perfect for kids who can use a rod and reel or anyone who isn't an "expert"....when they are hungry, which is most of the time, they are pretty easy to catch, fight good and eat as good as anything that swims.
I don't know how late in the spring the bite tails off because I have always started chasing crappie before the end of duck season on the lake itself and then bass and only bream fish the river to any extent after May or so....but I suspect yellow perch can be caught in numbers below the dam year round....it is really easy though from about November until the end of January and probably later in the spring....I also don't know a lot about fishing below Stevens Creek as it is difficult to access with anything other than a kayak but I would bet they catch them below that dam also. Probably below the bluff lock and dam also but I have never tried it. To easy and to close to the house to fish the river just below the dam.
They are also plentiful in the lake itself...seldom do I ever catch any number of crappie that there aren't a few yellow perch in the mix....but they seem to be smaller on the lake than they are below the dam for some reason....probably kept in check by stripers below the dam LOL. There is also some good bream fishing in that area....big shellcrackers and blue gill.