Think of all the things your father likes and create the day around him. Type up an itinerary of the day's events for him to follow and tie a big bow on it!
Here's an example:
9 a.m. Breakfast
10 a.m. Get ready for big adventure
11 a.m. Boat ride and fishing
12 p.m. Lunch on boat
4 p.m. Nap
6 p.m. Dinner (Dad's favorite meal)