You can set what the first visible cell will be when the file is opened using the FirstVisibleRow and FirstVisibleColumn properties.
var workbook = ExcelFile.Load("Book.xlsx");
var worksheet = workbook.Worksheets.ActiveWorksheet;
// Set last row which has some data as first visible row.
int lastRowIndex = worksheet.Rows.Count - 1;
worksheet.ViewOptions.FirstVisibleRow = lastRowIndex;
But note that this only affects the view, the selected cell (or cells) will remain the same.
If you need that as well, then you can also add the following:
// Set first cell in first empty row as selected cell.
var lastCell = worksheet.Rows[lastRowIndex + 1].Cells;
Does this solve your issue?