i think it should be okay, maybe just take a few stops to stretch your legs.

my cousin is flying out from the states tommorrow to come to melbourne to have her baby (she is from here but lives over there and her mum and dad are here and her mum has breast cancer) so that is why she has chosen to come back home for the birth. get this she only has 6 wks to go - OMG i can't believe she is flying and that the airlines said it was okay.

so based on that i think driving for 3hrs should be fine. have a nice time at the wedding