Jackeroo 3-way fridge advice please.

A mate has lent me this 35 ltr fridge [model J3PR35L] to take away and try over Easter.
He purchased it at Kmart $300 and has not yet had the opportunity to use it, so its still in the box.

Ive had it running for approx 12 hrs on 240 v and seems to be doing the job....just a couple of queries though.

12v.....90W - 7.5A, comes with a cig plug connection.
I already run a Garmin eMap and a GME 3220 uhf off the cig lighter plug. Would adding the fridge be too much for this circuit to handle ?

Will be running it on gas for 3 days while we are camped and would like to know if any owners have been happy with the fridges performance in this mode.

The reason I ask is that Ive always been an icebox man and if the fridge is not a great performer in 12v or LPG mode then it will only be a waste of space taking it,[as if I havent got enough gear to cart anyway]

Thanks for any advice or tips your able to give me.

Cheers.....Lionel.