For one you are going to need an ice chest in there - probably a big one. I put my ice chest behind the last seat. Put some hooks on the floor and bungee the thing down by the handles. It is in there to stay and it is out of the way, but can be removed from the ground pretty easily too.
Floor plan is soley up to you. I'd just start fishing with it and seeing what you want. I fished mine for a year before I knew what I really wanted it setup like. If I had it to do over again, I might go with a tiller steer instead of a console. For all my wanting of a console, it just kind of gets in the way. It protects things from getting steped on, somewhat. But I mounted my fishfinder to the top and now don't have a place to put the fishing bags - DOH!
Wiring and electronics is what you make of it. I bought a sidefinding fishfinder and love it, but I bass fish. Most times for roaming fish like trout and redfish, you know where the reefs/grasses are already. I'm not sure it would be all that helpful. I would think GPS/ depthfinder would be great on your boat.
Oh and buy a RPM guage for your Force motor if it doesn have one already. I blew my 40hp Force up that was underpropped/overreved. That was an expensive lesson.
Welcome!