Quorkle. Any kids or adults can play. Line up shapes on tiles, same shape, different color or same color different shape. All kept in a canvas bag.
Also double 5 dominos (for space) or double 12 dominos for Train and Chicken Foot. I use the white plastic tiles, but the old fashioned black wood tiles are far lighter.
If you just want to occupy them, the peg board solo games where you try to remove all the pegs one at a time, but jumping can keep them occupied for hours.
One other thing: We often have our grandkids with us. Small kids.
We put them on KP. the first time I said that, they all said,
I made it a mystery for the day, until I finally said, " You and You, go into the trailer and tell grandma you are on KP."
Of course she gushed over them, saying things like" Oh, wonderful, such good boys,"etc. they were thrilled to help, bringing out dishes, and place settings. One kid inside and one opening and shutting the bug tent.
From then on, all 4 of them wanted a turn, and for that period of time, they are occupied, busy, out of underfoot, and not fighting each other.
In summer, we also have squirt guns, and a small pool, which they really appreciate.