Australia and New Zealand

See this recent post:
https://community.ricksteves.com/travel-forum/beyond-europe/australia-and-new-zealand-tour

Liz, I’ve been looking and having severe sticker shock……

Which areas of Australia and NZ interest you?
There will be niche tours available in various parts of both countries.
You have to realise Australia is 80% the size of the USA but has just 7.5% of the population with more than 40% of that population in just 2 city metro areas (Melbourne and Sydney).
NZ is larger in area then the UK but has just 7.5% of the population.

Will be interested to see the replies.

I'm booked with a UK based tour group for a 30 day tour of Australia going in September 2023 (but may bring it forward to March 2023). Difficult to find something completely comprehensive - I think I will only have one opportunity to get to Australia. Would also like at some time to do NZ. I was planning on doing them as two trips, as they will both take some time to do well.

One tour company, I know of, based in the USA that does trips in that region is Collette travel. But I have no experience of them.
https://www.gocollette.com/en/find-your-tour

A trip to Oz or NZ needn't cost an arm and a leg if you're willing to forego the luxuries of a comprehensive escorted tour from either the US or the UK and do some of the basic legwork yourself.
Booking your own flights and accommodations these days is pretty straightforward - that alone will save you a ton of money versus having a tour operator do it for you. Then, per wurundjeri's advice, book your own day trips once you're there... wherever "there" happens to be. From Sydney (for example) there are a number of highly rated and relatively cheap day trips to the Hunter Valley and the Blue Mountains. Exploring the beautiful city and its environs by bus, train & ferry with a cost-effective Oyster card is easy too - as well as being a lot of fun.
By using the Qantas low-cost carrier JetStar you can move around within Australia cheaply and efficiently - opening up the option of adding visits to Cairns (for the GBR) or Uluru for a taste of the Outback onto your itinerary. Likewise, Air NZ offers cheap fares within that country as well.
If you're able to visit the two countries on separate trips by all means do it that way. Both are absolutely stunning tourist destinations and each deserves more than a cursory look.

Wow! Great advice

"Booking your own flights and accommodations these days is pretty straightforward - that alone will save you a ton of money versus having a tour operator do it for you. "

Not true of all tour companies. OAT will book you on airline flights that are less expensive than the ones they advertised at the lower fare.