In my "past life" I was a children's minister. I don't think you ever really leave that, but I realized that working for the church is toxic to my faith. That's for another story, though.
One of the things I invented (or think I invented, since I made it up without google!) for my first church was a variation on the stations of the cross for kids. It was designed for a large group with several adults, but I think you could easily change it to work with a family, so I'm going to give both options. I did this with 5-11 year olds, and it was by far the most impactful thing we did, and the thing the kids requested to do again. It seems a little macabre reading it, even though I've done it and it was great, so just have faith that children have a greater capacity for understanding than we do.
Here we go!
1) Explain to the children/child the purpose of what you're about to do is to remember Jesus' life, death, and resurrection. It will be fun in parts and sad in parts, but a spirit of reverence is required. If you're in a church setting and have the people, having someone dressed to play Jesus can be helpful. They don't interact with the children, they simply go through the motions and act as a line leader. Have the children remove their socks and shoes, and, if you have help, place them at the last station.
2) Last Supper. Set up a room (your kitchen will do nicely) with a glass of wine/grape juice and bread/matzo. I like to cover the table in a nice cloth and light candles, too, so that the room seems different than normal. Read the story of the last supper from Matthew 26:17-30, Mark 14:12-26, Luke 22:7-39 or John 13:1-17:26. You can pick whatever gospel you'd like. In a church setting, having several adults in "Bible Times" costumes and a pastor who can administer the consecrated elements (if your church serves children communion) is a nice plus. If you have a Jesus figure, they can do the reading of Jesus' words.
3) Move the children to an outdoor location, if possible. A garden, shady spot in the woods, or outdoor chapel if you're at a church all work nicely. If it's too cold, you can always assemble your indoor plants/faux plants to "make" a garden, or you can use a painting of Jesus praying in the Garden. I happen to really appreciate the Spanish painters like El Greco, but you can use anyone you want. If you have little children, they might need something for their hands to do, and this free printable of Jesus in the Garden is an option if you have a table or flat hard surface for them to color on. If not, that's okay, because my preference is to tell the story of Jesus praying in the Garden (Mark 14:32 or Luke 22:39) and then lead the children in a prayer thanking God for Jesus' obedience to him, even when it was hard. If you have a Jesus figure, when you first arrive in the garden, he should kneel and pray.
4) If you are in a church setting, a few guards will come in handy to come and remove Jesus. If not, tell the story to the children, and have a sword or some heavy chain available to give them a visual. Tell the children about how the guards taunted Jesus, and gambled for his clothes (have some dice available) and put a crown of thorns on him. In our back woods, I was able to find brambles and make a crown with thorns. I think that any physical representation you can give the children is helpful. One little girl in our group cried the first time she touched the crown because hearing that Jesus suffered for her was abstract, but touching the thorns and realizing he actually hurt helped her understand the reality of the situation. She wasn't in any way traumatized, she just had a real connection to the Easter story in a way she hadn't before.
5) Next, you'll need a decent sized cross. Most churches have these, and you can borrow one, or if you're in the church, you can use one. Lacking a pre-made cross, you can secure two large branches. You want them to be heavy, but not completely overpowering so the children hurt themselves. Ahead of time, prepare a hallway or outdoor area with sand and dirt. You can place the sand on disposable baking tins or a tarp if you're indoors. Explain that Jesus was forced to carry his cross, and tripped several times from exhaustion. Allow the children to drag the cross for a few feet over the dirt and sand.
6) Take the children to a darkened room with a second cross. I made this one out of two branches I nailed together (carve a groove in the cross-piece so it fits snugly on the post). Read the story of the crucifixion or just talk about how Jesus willingly went to the cross for us to take our sin. Give each child a piece of paper and allow them to write something on the paper or draw a picture. Explain no one else will see them. Allow them, with supervision, to nail or thumb-tack their sin to the cross. Your Jesus can disappear at this point.
7) At this point, you need a little emotional reprieve for the children. Ahead of time, prepare sheet pans with parchment paper (so you can write each child's name) and crescent roll dough triangles (1 per child). Explain how Jesus' body was quickly prepared for burial so that the Sabbath laws wouldn't be violated, but he would have been anointed with herbs and spices (roll a marshmallow in melted butter and cinnamon sugar) and covered in a shroud or bandages (wrap the marshmallow in the crescent dough) and placed in a tomb (place the crescents into the oven). Almost Unschoolers has a great full tutorial on this with pictures.
8) Ahead of time, prepare a tomb. I used a combination of tables, chairs, and cardboard that I covered in black banner paper from the teachers store, and a large "boulder" cut from cardboard (dumpster diving in your local appliance store's recycling bins with their permission is very helpful for this). We talked about tombs in Jesus' time and how Jesus was given a donated tomb. The children were excited to be "sealed" in the tomb. If you have soldiers, this is a good time to "post" them outside your tomb. At home, sheets or blankets fort-style would work. Take the children out, "seal" your tomb with stickers, tell them the story about how Jesus was laid to rest and 3 days later Mary and the women came back to the tomb. You'll need to time this with your baking time so that you can show them the 'empty tomb'. Jesus was risen, just as he promised.
9) Finally, move to a prepared location with tubs of water and towels. This is where the children's shoes and socks would have gone if you moved them. Explain to each child that God wants to be with us so much, but because he is perfect, he cannot be marred by our sin, so he had a plan from the very beginning to wash us clean so we could be with him. Jesus' life, death, and resurrection enable us to be made fit to live with God forever in heaven. Accepting Jesus into our hearts washes us clean. Wash the children's feet, using whatever words of forgiveness your church traditionally uses for a footwashing. Dry their feet and help them put their shoes on. I like to offer them the option of having someone to pray with (in a large group) and set up a coloring station for the children who are ready to be done and/or respond in a written way.
10) Pray the group out, or, in a church setting, the pastor may wish to offer a benediction.