This truly is a deal if you are coming to Altoona with a family. I would suggest you plan at least two days for your visit, but 3 would be more relaxed.In the summer, I would start either day with a trip to either Horseshoe Curve or Fort Roberdeau, as they are both outside and it tends to get hot/humid later in the day. After that, you could go to either Baker Mansion or Railroaders Museum. Then hit either Lakemont Park or DelGrosso's amusement parks for lunch and the rest of the day. Both parks have waterslides and over 30 rides and amusements.
Here is a sample itinerary
DAY 1)
9am Railroaders Museum (3 hours)
12:30 Horseshoe Curve (take a picnic or buy snack there).
2pm Head to DelGrosso's Amusement Park. Plan to eat dinner and spend rest of day there.
Day 2)
9am Baker Mansion (2hours)
11:30am Fort Roberdeau (1 hour)
1pm Lunch-Lakemont Park
Spend the rest of the day here with Waterpark, rides and amusements.
From journal History,Heritage and Hospitality in Western Pa.