I would go, and take bub. You need to think how important the wedding is to you, and if you will have any regrets if you dont go... but the sounds of it, you would.

I hired a car seat and stroller in Qld when I went up in November (bubs was 4 months at the time) and they were in great condition, looked like new. If you (or DP) are worried about the installation just take it along to a professional for the extra piece of mind.

You can also take a car seat with you as extra baggage, I know with some airlines you dont have to pay extra for babys stuff, i.e pram, car seat etc. I didnt take mine as I went to airport by myself and didnt have the hands to carry everything!!

When I went to Qld last year, we couldn't afford for DP to come. I asked my mum for help as my xmas present. Luckily I didnt have to hire a car or pay for accommodation, is there anyone you could stay with??