Congrats Latitude on your new KSDP.
On a gas coach there is a panel on dash that lifts up to access the fuse panels and CB Ant.,12v wires are coiled to left of fuse panels. 12v's for GPS can be picked up from the AUX 12v outlets on dash face panel.
I have two outlets next to CB radio. There are spare fuse locations on fuse panels that you can use a fuse clip to bring off 12v's.