For the RCA's and turnon wire, I went around the bow, on the inside of the lower part under the seat cushions. I had bolts through there for the bow filler cushion supports. I mounted the amps on boards that I made from Home Depot cutting boards carpeted with Lowes marine carpet, close to a match. I cut away a square of carpet and glued an MDF board about 6x8 to the hull, screwed the board to that.
For power, I came up from the bilge into the storage compartment, there is an access hole. I put a second battery in there. The boat I'm talking about is my D drive epic 22, battery in the floor.
There's plenty of room for a sub under the drivers foot panel, made a nice box.