I did a 69 RoadRunner restoration for a gentleman last year and he wanted the interior to have road runners in different places in the interior so we took parts of the interior to an upholstery shop that does embroidery. They stitched road runners on the door panels, Frt/RR seats, dash pad, and center console cover.
On my present shop truck I had the head rest's done with crossed Chevy/checkered flag logo's on the front seat head rest's and "Chevrolet" on the rear seat head rests.
If you remove the pieces and bring them to the shop it's fairly inexpensive.
For exterior items locate a vinyl graffics shop, most of the graffics they do now are on computers and they print off the design, I'm sure theirs a local shop that could do something "Hello Kitty" to put on the doors, hood, and tailgate.