Thanks to all for previous help on planning our upcoming trip.

A few questions remain that I could use opinions on. First, for Sydney day trips, is it best to book in advance on line, or can they be booked day by day once in Sydney> We will be staying at the AEA Bridgeport so Circular Quay will be convenient if it is possible to book there. We are planning a Blue Mountains trip, a Hunter Valley winery trip, and a dolphin watching trip at this point. For our other Sydney days, we are planning an Aussie rules football game, the zoo, the aquarium, and something at the opera house during our 6 full days there the end of May (plus travel days on each end).. The flexibility regarding the weather would make booking after arrival desirable if it can be done on a walk-up basis.

We are then flying to Cairns for 3 full day (plus travel days on each end). We are staying at the Bellview downtown, and were advised to book trips depending on weather after we arrive. We are planning a reef trip, a Kuranda rail/skyway/aboriginal park trip, and a half day fishing trip.

Comments or suggestions about our choices and options would be most welcome.

As far as weather goes it is always best to leave planning a trip until you get somewhere if you have scope for that and it looks like you do for it is only really the Zoo and Blue Mountains you do not want to be doing in any drizzly/rainy weather but late May could see you having reasonable weather.

You'll need to check for the www.afl.com.au for the Sydney Swans are the only Sydney based side and they'll either be playing at home or away. If away, have a think about seeing a rugby league game www.arl.com.au it could be, about size of a Grid Iron field with some similarities but a lot different, minimal padding and no helmets though a few players do wear padded headwear.

But other than that you might want to check in advance what is on at the opera house and some shows are popular so I'd book for there, wine trips are fairly plentiful and Acquarium/Zoo you do not need to book for nor should you have any difficulty doing the dolpin watch cruise.

So I'd see what the weeks weather forecast is on arrival and plan on getting up to the Blue Mountains for whenever best day looks to be and also fit the Zoo in when it's not raining if there is any about.
Though a number available, you do not need to book a tour for the Blue Mountains if you do not want to as you could catch a train to Katoomba and then use either the Explorer or Trolley Bus companies that have buses doing circuits of different lookouts and cable car/scenic railway locations, a whole lot cheaper than a tour.

Another alternative you may want to consider if you have not booked all accommodation[or can change some] and do not mind some driving is to arrange a hire car and head out to Blue Mountains [perhaps via Featherdale Wildlife Park], stay overnight at a nice B&B, take in Zig Zag Railway and Mt Tombah Botanical Gardens on way down to Windsor and Putty Road across to Hunter Valley and another night there and then you have the options of taking in Port Stephens and possible Dolphin watch/maybe a swim there before heading back to Sydney or driving about another 1.5 hrs north for Forster/Tuncurry, staying overnight and Swim with Dolphins there before heading back to Sydney.

Cairns weather should not be too bad but again there are plenty of reef trips and so you ought to be able to book for reef/fishing on arrival to suit weather and ditto Kuranda etc.

Good advice from Bushranger.

Shame you don't have time to see the area around Cairns.

Looks like arl was got by the retailers and so for rugby league it's http://www.nrl.com/ or www.australianrugbyleague.com.au or for the game they say is played in heaven - http://aru.rugby.com.au/ , I think God must be a messy person though for it's a messy game at times and takes a bit of getting used to rules - some very technical applications and then at other times head stomping allowed.

And re Cairns, yes it would be good to try and give yourself another day there and you may want to just see how you go with arranging Sydney to swap a day.

And for extra time, have a look at flight times www.webjet.com.au for from memory first flights are about 6 am departure from memory, so you'll have less people in terminal to deal with and be in Cairns by about 9 am or not much after, and same back to Sydney, look for late afternoon evening flight if it suits.

You shouldn't need to book in advance for day trips from Sydney in May- it's not high season - and you do want to do what the weather suits.