I've done the gorge 2 times in the past few years. Bit of an unhill climb going in, but not too bad, and back is mostly downhill obviously. Lots of forest and places to cool down though. Think its 11km in total.
Wanted to camp at Rugged Glen, but did not feel safe at all (probably due to no other people !), so booked in at Mahai, at least it was only 1/4 full. Yes, the fact that there is no view of the Amphiteatre is a bit sucky, but I guess you only have to walk a 1km or so to get a proper view.
Climb the chain ladder, and boulder hopped for 1km or so, but turned around as it seemed to much of a mission to continue. also went up to the cave (to the left at the chain ladders/tunnel), nice view of the waterfall from there.