Sounds like fun !
I agree with the health & safety issue, the only time we did a plate smashing stall it took forever to clear up after even with heaps of floor coverings, love the paper plate & tomato idea
although wet foam balls could be an alternative !
Are you dressing up the stalls with gingham ?
Game ideas could include a double sided picnic basket for a lucky dip ..or hunt the numbered horse shoe in a barrel of hay, match the number pulled out to the prize , country & western tombola
lol
Hula hoop Hoopla over soft toys instead of traditional lasso perhaps !?
Toss the cowboy boot !
What things are you already planning to do ?