I was leaving the US in December, and would not be returning prior to my planned visit in April.

.. could have got a Visa Grant valid for six months in December or with a US passport even a five year multiple entry.

Wow - $1500/week, plus 16% tax, plus gas, food. I don't see the upside in that equation. I think I paid about $350 for two weeks for my sedan - took me offroad, through the sand, everywhere I wanted to go. I used Cactus Car Rental - reservations online. When I was camping at Sol de Mayo and Los Arbolitos, there was a group of 4 German guys, who coincidentally were at both locations the same time I was. They didn't even have a tent - it did rain for a short time one day while at Los Arbolitos (I was there 3 nights - awesome), but it is possible to rough it, and combine with hotels if necessary. Check out the BuenaVista Spa Yurts - about $35/nt. Todos Santos Hostel - private rooms are $50/nt I think. There are AirBnBs too. Go and have a wonderful time. BTW, the most useful and appreciated piece of gear I had was a small, lightweight fold-up chair that had a back. Packed away it's about 13"x4"x4". Brand called Outad - available on eBay for about $12 (at REI for $75).

Yo FCG: one of my best friends (former bassist in our band, world-class player) married a gal from New York. Her aged uncle is apparently one of the most senior religious figures in Poland. As a result, my pal and his wife have vacationed in Poland annually for many years now, getting 'backstage' in ways that'd otherwise be impossible. Your itinerary sounds much the same as what they did on their most recent trip. To hear those friends tell it, the food at the main cafe for the Tatra hike was worth crossing an ocean for, as were most meals in rural areas.
Have a great trip! Bonne chance.
I am done. The perogi.

Thanks for your reply, as far as we are this is our outline:
- we’ll arrive in Melbourne and will be hosted by friends that live there. Arranging all kind of things, buying stuff and gear and get used to the car. Eventually we’ll do a first trip to the mountain area to get used to the car and to discover eventual issues so we can solve them before we hit the road
- We’ll start travelling one month in Tasmania (taking the boat), going from National park tot National park. I’ve been cycling there in 2003 and I know there is a lot of things you can do without 4WD (almost everything). Some gravel roads in the NE, but they shouldn’t be a problem.
- Back again in Melbourne, we’ll head to SA where we’ll go to spots like Kangaroo island, flinders ranges and make a loop in the Eyre peninsula. I would love to go inland too to visit the salt lakes. I’ve looked on Campmate and I saw the most remote camp spots are often only accessible by 4WD - there it will give us an extra freedom we would not have with a regular car. But there might be solutions in between that still give us acces to a lot of unpaved destinations. I’ve been to Flinders ranges in 2003 too and I remember it cannot be properly experienced without leaving the sealed roads (in contrary, it only gets nice from the moment you leave the sealed roads).
- there will be 3 or 4 weeks left to cross the Nullarbor plain and make a loop around the SW of WA (Albany, Esperance and also Kalgoorie) before heading to Perth. We won’t go much north of Pert. Haven’t checked yet the necessity of having a 4WD there, but found on Campmate again some nice remote spots for 4WD only.

Some extra thoughts:
- Arranging things like rego in Adelaide should be planned before we do the loop in the SW, that would kind of disturb the rythm of our roadtrip and maybe it will cost us some time. We’re not that much city lovers.
- About the 4WD, it’s a legitime question if we really need the real stuff like a Nissan Patrol, Landcruiser or similar. There might be intermediate options but these vehicles are often smaller too (like a Subaru forester for example) and at the end, we still need to carry five persons and a lot of gear. Been thinking about a small trailer but that means also we’ll need to sell it afterwards. Ideally we could find an equipped trailer (tent, cooking gear, fridge,...) making it attractive to sell to other backpackers afterwards.
- renting a 4WD is way too expensive, especcialy if we want an equipped one. Renting a van could be on option (still very expensive for three months) but main problem there is that we probably could’nt do any unsealed roads. As we often look after remote spots, wouldn’t that be frustrating to see nice spots while travelling but to not be able to drive to them because of the rental restrictions?
- about the idea of doing a one way road trip instead of a loop, since we’be written this post we start to hesitate for doing it one way. It gives a clearly more issues to solve and we really want to spend as much time as possible on funny things. Getting back to the idea of making loops from Melbourne could make it easier to organise everything. In that case, we will need off course to skip WA. That will give us more time to spend in Victoria and eventually we could make the crossing from SA via Mildura too Sydney and then head back to Melbourne via the coastline. Then again, no idea of 4WD necessity.

Hope this is enough outline to incite you to some advisory thoughts on our family roadtrip. We are clearly suffering by ‘the embarrassement of choices’ while we need to decide and buy our tickets as our departure is coming closer. So any advice is welcome. Just bear in mind we’re not roadtripping as we would do if we were just the two of us, we have three small children to entertain all the way along. That will anyhow influence the itinary, daily distances to travel and spots we’d like to stay.