Rooster,
It depends on where you are planning to fish. If you are going to fish in US waters, the first couple of weeks in May always produces for Smallmouth. Remember about the regulation change on Lake Erie this year. You can fish for them but you can't keep them until the end of June. So if you are looking for a wall hanger, this isn't the time of year to go.
If you are heading to Canadian waters as many charters do, they have a closed season until the last Saturday in June. The fishing over there can be awesome.
Another great time of year for all of Lake Erie is late September to late October. the fish go on a big feed before the winter. I hope this helps.
Wes