I did not know your grand father, but I can help you with a little accumulated information and experience.
He possibly sailed from NY P/E on 6-3-44 on the AQUITANIA, with other replacement troops destined for England, arriving on the 6th. or 7th of June.
Had the sailing been a few days later, he would have been on the QUEEN MARY.
His unit was the 298th Infantry Regiment, not the 298th Infantry Division, which never existed.
He was in the 75th Infantry Division, which included three Infantry Regiments (289th, 290th,291st), four Artillery Battalions (730th,897th,898th,899th), six Tank Destroyer Battalions(628th,629th,654th,772nd,807th,814th), among other elements.
Campaigns: Rhineland, Ardennes-Alsace,Central Europe.
According to CITIZEN SOLDIERS, Stephen E. Ambrose, author, the 75th ID entered the line 25 Dec 44, and had 94 days in combat. It suffered 56.9% casualties.
Commanders: Major General Willard S. Paul, Apr 43 MG Fay B. Prickett, Aug 43 MG Ray E. Porter, Jan 45.
Casualties: Killed in Action, 817 Wounded in Action, 3,314 Died from Wounds, 111.
If you will refer to the following postings, you will find more information related to his battle experiences: #848,#868,#1281.
I hope that this proves of benefit to you and your family.