Summer of 2005 I did a number of try-outs inspired by watching Notting Hill yet once more in a Mexican hotel. This one uses 4 P4 people, so it fits your 4th birthday theme.
The characters - an idealized LightWriter and his Better Half on the left, their Chick and her Hubby on the right. LightWriter and the Better Half were the idealized 40+ portrayed some time ago!
The scene - Richabri's (I think ;-)) Jen's Garden, the trellis on the left is Zippy's prop I think it's called a Raspberry Trellis, and the sapling on the right is part of JSRoad's hedge (really a row of 5 saplings parented to tree No. 1).
I also did a cartoon render of this, I used a late beta of DAZ Studio because my new company lap-top didn't run Poser 3 and I hadn't bought Poser 4 wet, so the cartoon grass turned out black.