A way to combine different grade levels for the Stations of the Cross for Children is to have each grade write about a station. They can use Bible verses and/or write about something that the station means to them as a group by grade. When each station is completed, review them. You can compile each station into a booklet and/or have a designated person read at each station.
Start with an opening prayer, Lord's Prayer, Hail Mary and Glory Be.
Have 1-2 people at each station to read.
Start with the First Station - Jesus is condemned to death.
(Leader says, "We adore You O Christ and we praise you." All genuflect and all say "Because by Your Holy Cross You have redeemed the World" after announcing each station.)
The children or youth then read what was written for that station.
Then repeat above at each station.
At the end - have a closing prayer with Bible reading. Finish with the Lord's Prayer, Hail Mary and Glory Be.
You can do this with older youth too. Just change the grade level for each station.
Another activity that can be added is to have the children color a picture for each station and post them around an area for "their own" stations to walk.
My project below can be downloaded here.