mmm... no tripod? guess gorilla pod may be a good choice. Its lighter to carry for holiday anyway.
few things i will do for shooting fireworks in e park.
Choose a spot where no people can stand infront of you. e.g. my last trip to HK Disneyland, as i was using a gorilla pod. I have to position myself behind a short fence covering a small garden inorder to mount my tripod. I realise that its a good choice as no body can stand in the garden thus no BIG heads to block the view.
oh yes, if possible look out for the wind, hope its coming behind u not towards u.
I will opt for a ultra wide angle lens. something like a 12-24 etc. settings wise is will go manual, abt 6-8 sec, F8-11, ISO 100. Black card and remote will be useful too.