With a belly full of butter beer, every flavour beans and chocolate frogs, I find myself hurtling along – somewhat queasily – atop a broomstick, as I try my best to evade a fire-breathing dragon in my rush to get to a Quidditch match. So far this morning, I have visited Ollivanders and been chosen by my first wand, flown with a Hippogriff and dined heartily at the Three Broomsticks.
Imagine you are the most popular author of all time, at least as measured by royalty cheques. What do you do next? In the case of JK Rowling, you get involved in designing the Wizarding World of Harry Potter at Universal Orlando, the latest attraction in the Florida theme-park capital.
You may have gained the impression that this is a brand-new theme park. True, it opened only this summer, but in fact is just a corner of the vast Universal property, replacing a rollercoaster now past its thrill-by date. Even so, the Wizarding World of Harry Potter makes an impression by dint of the huge castle sitting on top of a man-made mountain.
The impressive building houses the "Forbidden Journey" ride – which is neither of the above. Far from forbidden, it is something that every visitor should try. And it isn't a journey, either, but a simulator that purports to take visitors on a mini tour of Hogwarts, past the Sorting Hat and through Dumbledore's office before launching them into a broomstick ride with Harry Potter himself.
The Wizarding World also has a rollercoaster called Flight of the Hippogriff, which is aimed at children. Now perhaps Floridian youngsters are made of stronger stuff than I am, but it left me embarrassingly shaken. Worse was to come: the Dragon Challenge, a bona fide adult rollercoaster, sees two dragon-headed trains of riders flying through the air on separate tracks. The two cars go through three "narrow misses", which have many convinced they are about to crash headlong into an oncoming mythical, fire-breathing beast.
The ride begins by cranking both cars up a steep incline side-by-side. The brave and the downright foolhardy – myself included – lean over to wave at and taunt their counterparts, sometimes in blissful ignorance of the terrifying thrill that is about to come, sometimes in nervous anticipation of it.
After that, time for some food (eating before Dragon Challenge is not recommended). Choice of venue is limited – there is but one: the Three Broomsticks, incorporating the Hog's Head pub. And it is expensive.
Afterwards: well, having exhausted the thrills in a morning, best devote a leisurely afternoon to shopping for chocolate cauldrons and wands in the themed shops.
At its opening, some old Orlando hands said that the park's success could be jeopardised by the length of the queues. The lines have yet to be tested fully by the Christmas and New Year crowds, but already some families have found themselves standing for up to two hours at peak times. At least Thierry Coup, the park's designer, has thought to incorporate lines into the rides. The queue for the castle, for example, feels more like a tour of Hogwart's than the more traditional stand-and-shuffle.
After being on my feet all day, I had the option of travelling back to my hotel, the Loews Portofino Bay, by water. The hotel – and attached lagoon – are built to resemble the Italian bay of the same name, with little ferries carrying guests to and from the parks. The closest central Florida gets to tuk tuks carry those unlucky enough to miss the boat and who don't fancy the 25-minute walk along the waterside.
The relative excitements of Harry Potter are stepped up a notch after dark. Hallowe'en is a much bigger event in the US than in Britain, and for the past 20 years – long pre-dating Harry Potter – Universal has offered "Halloween Horror Nights", where ghosts and monsters lie in wait to leap out of the gloom and scare guests out of their wits. They are staged intermittently from late September until 31 October itself.
Each year takes a different theme and this time around, the designers have decided to bring together their biggest hits in what they call "the manifestation of fear itself".
In practice, that means guests are confronted by eight houses of horror in the form of four to five minute-long mazes. From a walk through Hades to an encounter with mass-murderer Cindy in her blood-spattered orphanage, the houses are filled with live actors in terrifying costume with one intention: to scare their guests. This is not an event for youngsters; indeed it is not recommended to children under 13.
Of all the tactics employed to trigger a scream of terror, it was the most subtle which terrified me the most. In a strobe-lit room, with bars and obstacles swinging from the roof, designed to disorient – and mirrored walls to multiply the confusion – I got hopelessly lost. The lights flashed momentarily on and a girl suddenly appeared, staring menacingly, straight into my eyes. The lights went out and she disappeared just as quickly. Subtlety was not exactly the order of the day, but her stare left me rooted to the spot until the lights had gone out again.
In another house, guests were allowed to enter what appeared to be a relatively benign room before actors jumped out from all angles, cornering the group and sending one or two into a blind, panicked run out of the door to safety.
As part of the event, the whole park is transformed by night into a succession of "scare zones" where men with chainsaws roam. They have a penchant for singling out one person in a group and revving up their chainsaws before running down their victims, banging the weapons on the floor around their feet.
A stay here is predictably shot through with a very American take on Hallowe'en – and most of the people staffing the Harry Potter park possess local accents, rather than British ones arguably more befitting JK Rowling's original books. But there is no doubt that the people at Universal Orlando know what they're doing. If British cynicism can be set aside and the Wizarding World and Horror Nights taken for what they are, there is plenty of entertainment to be had by all ages.
With all that is on offer at the two events, it would be easy to forget that there are also two older parks to visit: Islands of Adventure and Universal Studios, which house rides like the thrilling rollercoaster "The Hulk" and "The Simpsons simulator" as well as three water rides. But many will still be keen to spend the majority of their time at the Harry Potter theme park; perhaps it is not exactly Hogwarts itself, but it may be as close as us "muggles" will ever get.
Travel essentials: Orlando
* The writer travelled with Virgin Holidays (0844 557 3859; virginholidays.co.uk), which offers seven nights in Orlando from £1,299 for adults and £499 for under-16s. This includes Virgin Atlantic flights from Gatwick or Manchester, car hire and room-only accommodation at the 5V Loews Portofino Bay Hotel at Universal Orlando. Prices are based on two adults and one child sharing a standard room, for departures in January 2011. Access to the VRoom at Gatwick Airport costs £17 per adult and £10 per child.
* The Wizarding World of Harry Potter: universalorlando.com/harrypotter
* US visitors require a $14 (£9.30) ESTA permit ( esta.cbp.dhs.gov).