You hook your Power Inverter high DC current unit directly or as close to the battery as you can with the DC side. I would also install a 100AMP DC Fuse in this line for your 1000WATT Power Inverter. It will draw around 82AMPS if fully loaded down to full output.
Then you can run the 120V AC side of the Power Inverter using extension cord etc about as far as you want to be away from the Power Inverter without any loses...
I Installed a couple of the multi-head drop cords like shown below with one at the Home entertainment area and the other back near our bed where we like to charge up a bunch of thing and have a couple of 120VAC low wattage devices we use a lot of. I have these multi-head drops mounted on the back of a cabinet top out of the way... These have their individual ON-OFF and breaker protection on the head.
Everyone knows this is 120VAC Pure Sine wave backup source of power...
I just leave my Power inverter running all the time and have the Home Entertainment items plugged into it... It only darws a small amount of DC current when jus sitting there not being used... I would also only use a PURE SINE WAVE Power Inverter so that no matter what gets plugged into it you don't have to worry about the dreaded BLUE SMOKE..
We could easily hide the extension cord running along the wall to get from the Power Inverter ... LOWES also sells some of those snap cable protectors that stick to the wall
Roy Ken