Would this be a good place to bring a group of senior citizens(Mostly wheelchair bound)?

Castle Rock Park north of the road has a couple pavilions to picnic at and some nice views but it's not on the river.

No its all stairs for castle rock look out

Although there are great views on pavement level but not recommended for seniors due to rough Terrain.....

There are great views of the Rock River at the ground level paved parking lot where the outllook tower exists. Also great views at the nearby park just north.