Big Dave,
I fish out of Conneaut. The weather/conditions in the western basin play a role since the effect the spawn, and hence when the spawn completes and the walleye start moving east. For walleye we generally start trolling in June, depending upon reports. We may start further west out of Geneva and Ashtabula. Some people in the area start as early as May. I'm sure there are wallye present in the spring, as not all spawn in the western basin, but I don't think the numbers are high enough to warrant trolling. We tend to just fish inland lakes in the spring.
Another idea if you want to get some spring fishing, depending upon strain, steelhead should be coming out of the rivers. Not sure what kind of runs you get on your side of the lake, but may be an option.