Alyndabear, I thought about just putting this in the comment section but then got worried you might miss it.
There isn’t really much in the way of preparation when it comes to taking your rabbits to the vet. Make sure they have water in their cage and maybe some food. The car trip isn’t usually stressful but rabbits are highly strung so it might be an idea to have someone drive while you carry the cage in your lap. Covering the cage so they are in the dark may also help. Don’t try to transport them just sitting in your lap. Plus once you get into the waiting room there may be a dog or two waiting. The rabbits are much safer in a cage or secure box.
Umm..that’s about it I think. The vet will usually give them a check over, ask if you have any concerns and then give them their jabs. From memory I think it’s only calici virus we vaccinate against. Here in QLD rabbits are pests so we don’t see any as pets. When working in Adelaide it was just the calici virus we were worried about. It’s probably the same for you (you’re in WA, right?).
Ok. Hope that helps!