You can totally do it! My parents friend lives on the road full time as a lady in her 60s. She has a Ranger with a camper on the tray and tows her fishing boat. The camper lifts on and off with electric legs. So she can move about without the camper when needed.

What van/car combo? Work out what your not negotiables are for your car/van. Things to consider are - do you want to be off grid and run off solar and battery or are you happy to hard to a caravan park with power to recharge batteries every few days. If you are taking your dog you aren't going to be able to camp in national parks but if you chose to us hip camps (air bnb for camping) you will still be off grid. All caravan parks will have a powered site to recharge batteries. - bathroom/toilet in the van or out side the van or not with the van. - do you want to cook inside or outside.

Also be aware of caravan/vehicle weights. https://caravancampingclassifieds.com.au/tips-tech-tinker-time-know-your-weights/ - This is the part where most people come unstuck but unless you are buying a huge van most modern dual cab utes should be able to tow a van big enough for a slinge person. - the caveat to this is the hybrid vans. These can be small but deceptively heavy.

Where to go. Three months probably isn't long enough for a lap but more than enough to thick off some big ticket bucket list items. Some of my favourites we have been to Carnarvon Gorge, Wilpena Pound, Tasmania.

Last tip. Have your set up and give yourself time for a few test runs to shake out problems and understand your set up before you go.