Hooking up a 750W inverter in a regular car.

So recently I got one of those PowerHouse 750W amps from Loves with some accumulated points(still got plenty of left over!!). Anyways, I primarily got it for road trips out to bicycle group rides and to also charge up the pedal assist battery on my recumbent trike between rides.
This thing obviously can't be hooked up to the cigarette lighter and needs a direct connection to the car battery.
Apart from perhaps getting some longer cables to go from beneath the hood and to say, the back seat where the trike battery would be, is there anything else really needed to connect?

Or is the simple connection to the 12v battery with alligator clips good enough?

 

I'm only looking at running a battery recharger for my ebike battery that runs at about 5amps/100v AC current. That's according to the charger specs on the site I got the entire kit from. Only other thing I could think of is just getting another 52v battery and using that for the second ride I head out to.(I pull a 100lb trailer with my recumbent trike and it allows me to keep up with the main pack!)
As far as the inverter installation, it doesn't sound too difficult. But it's definitely sounding a whole lot more than simply plugging and go.