Help me think of Scavenger Hunt clues for my son's birthday party!!!

[liliaceae]

My son's 4th birthday party is on Saturday, and I need to come up with clues for a scavenger hunt, but my brain is fried from lack of sleep. Actually I don't know if scavenger hunt is the right term.....I want the kids to find a clue indicating the next place to look, go to that place and find a clue for the next place to look, and so on.

So here are the places we could hide clues (they're all outside):
-in a sandbox
-in/under a sand and water table
-on/under a picnic table (which will have food on it)
-on/under a plastic slide
-on/under a little plastic school bus/slide thingy
-on a little potted pine tree
-in a garden
-under a raised, wooden deck
-on a green chair

The clues need to be easy enough for 4 and 5 year olds to figure out, but if they can't, there are adults there that can give them a hint.

If you can think of a clue for even one of these places, please help me out! Thank you, all you brilliant, creative mamas!

[liliaceae]

Nobody? Come on mamas, I know you're smarter than I am!!

[sweeetpea]

My morning creativity has its limits:

in a sandbox
"Dig for treasure on the beach, in the sand, just like a pirate"

-on/under a picnic table (which will have food on it)
"Ants like picnics and run to the picnic table; so does xxxx, so maybe it's there..."

-on/under a little plastic school bus/slide thingy
"Taking a ride to Kindergarten on a yellow school bus..."

-on a little potted pine tree
"looking like a Christmas tree ornament/present..."

-in a garden
"We plant flowers, and vegetables in a garden/in a special spot, but there might be something else there, too"

-on a green chair
"My favorite color is blue, kevin's is yellow, but xxx's is green, so can you see something green where yyy might be?"

[blessedwithboys]

Try pictures, it's way easier. When my friend and I did an indoor scavenger hunt for about 15 boys, we took a close-up detail shot of the hiding place. We gave them the 1st photo, they found the spot, and there was another photo there as the clue to the next hiding place. We had 3 teams and we gave them each their own path to follow, so there were 3 sets of photos total. This kept crowding to a minimum. I'm on the phone while I'm typing, so if this doesn't make sense, LMK and I'll re-clarify.

[liliaceae]

Thanks ladies. I think I'll probably do the picture thing, I think the kids would have fun with that.