Bridal Shower Via The U.S. Mail

Help! My sister is getting married in Las Vegas this June. She lives in Texas, I live in Ohio and many of the guests invited live in other states. I am planning a bridal shower via the mail. In my invitation, I am going to set a date for everyone to mail their gifts on the same day to give my sister a shower of gifts. Is there a right or wrong way to do this? Any help with how to word the invitation would be a great help too! Thanks a bunch!!