I am curious to know how you were able to get information to pay off the mortgage in your grandmother's name alone. However, if it is paid off, you should have received a release of lien from the lienholder.
Since there was a Will, any assets not specifically devised would pass through the residuary, as stated earlier. However, if the net value (defined below) of the mobile home does not exceed $50,000.00, you may be able to clear the title from your grandmother's name through an Affidavit for Collection of Personal Property. But title should pass to the devisees (her children, I suspect) and they can then convey to you. If the net value (market value minus any liens or encumbrances) of the home as of the date of your grandmother's death exceeds fifty thousand dollars, the home will need to be probated in order to clear title.