I really like the combination of Soft Sky and River Rock.
Here, the camper from Happy Camper was stamped in Soft Sky on Very Vanilla card stock AND a piece of regular paper (bond - thin, what most people keep in their printers).
The camper was cut out of the thin paper to make a mask. What that means if you put a little 2-way glue pen on the back of the cut-out image, let it dry, then stick it over the top of your stamped image on the vanilla card stock. Now when you stamp the trees in River Rock ink, you can go right over the camper. When you're done stamping, peel off the mask and the camper looks like it has trees behind it! It's a terrific advanced stamping technique everyone should learn/know.
I also recommend using a Post-It Note for your mask, though I didn't have one big enough for this camper. Then you don't need to add the 2-way glue.
The "happy birthday" comes from the cute 4-piece stamp set Bitty Birthday.