Help with wiring up a power inverter

I need to hook this thing up to an auxillary source. It uses 10 ga wire, so I'm guessing somewhere under the hood is my best bet.
Can anyone tell me where would be the best place without splicing? I'll splice if I have to, but would rather not.
Thanks for your input.

if i were you i would wire it straight to the battery,what size inverter is it

It's 400w two outlet.
Direct to the battery would be easiest, but I was hoping to not have to remember to turn it off every time.
Thanks

Whats the application?

I'm setting up a mobile office to run a lap top, printer and cell phone charger.
 
Any ideas???

Why not just add a small constant duty solenoid under the hood, triggered by a 'KEY ON/ACC' source? Or a decent sized/rated relay.. The inverter and cable run should be as close to the battery source as possible to keep the signal clean.. I occasionally run my laptop coupled with my cell charger off of a 150w inverter plugged into the power point and has worked fine... My GPS on the other hand,, is on a flex stand at my seat/console position, and 'was' tied into my seat power for a short convenience power tap.. Even without the seat in any kind of movement I was picking up a 'terrible' static when the GPS was playing music files into my OEM radio.. Moved the power source to the power point and it worked fine.. Point being, that tapping into another/shared source may/maynot affect functionallty.. Plus a more direct connect, should any more add in's be needed won't add any guess work to the system loads..

I went straight to the battery for now. I'll have to add a relay later. I just don't trust myself to turn it off every evening.
 
 
As far as the GPS, I'll leave it in the power outlet at the dash. It all should work together well.
Thanks for all the ideas.

When using a relay in todays vehicles, make sure you use one with a diode installed in it.  Like a BOSCH or FORD OEM unit.  The diode eliminates the voltage spike which can damage the computer modules in any vehicle.  A 12VDC relay can generate a voltage of 1,000 to 1,500 volts during turn-off. This voltage is duilt up in the energizing coil of the relay.  With the advent of modern electronic systems, this relatively large voltage transient has created EMI, semiconductor breakdown, and CPU failures.

 Absolutely true..
 
When a relays coil voltage/mag field drops, an 'inductive kickback' can occur.. With a quenching diode the voltage kickback spike is stopped..