This is what I did that does not involve using the Rect class:
I had a defined right lateral limit and determined whether the current string would be larger than the set bounds.  If it was, I wrote it.  Otherwise, I continued adding to it.
foreach (string field in temp)
{
    if (field == string.Empty)
    {
        continue;
    }
    else
    {
        tempSB.Clear();
        tempSB.Append(sb.ToString());
        tempSB.Append(field).Append(", ");  //append the incoming value to SB for size testing
        if (gfx.MeasureString(tempSB.ToString(), defaultFont).Width > 500)  //if the incoming string is bigger than the right bounds, write it and clear SB
        {
            gfx.DrawString(sb.ToString(), defaultFont, blackBrush, 50, currentLine + defaultSpacing);
            currentLine += 15;
            sb.Clear();
            sb.Append(" " + field).Append(",");  //add the overflow to the beginning of the next line
         }
         else
         {
             sb.Append(field).Append(", ");  //if it is not too big, append it
         }
     }
 }
 if (sb.Length > 0 && sb[sb.Length - 1] == ',') sb.Length--;
 gfx.DrawString(sb.ToString(), defaultFont, blackBrush, 50, currentLine + defaultSpacing); //write out whatever has not already been written out
I know I'm late to this question but I hope it can help someone.