Pretty much 100kph all over Oz when it comes to towing a trailer. I think that's about 62 mph.
No real frustrations towing the Tear. Must admit towing the caravan used to brass me off.
Like others we tend to use the roads less travelled as we are never in a hurry when towing the Tear.
If we are ambling we utilise the CB when mixing it with trucks. They tend to be big/long down our way. Makes life easier for them and us.
Take it easy.
RD