I don't really have any experience at trikes, so can you folks tell me the differences between them and upright bikes, as regards the basics...??
It's a recumbent, which means it's heavier and more aerodynamic than what you're used to. You'll be slow up hills and fast down them. Conservation of momentum is key to making progress.
You've got a seat to push back into, which means you can generate more torque on the pedals than with traditional honking. Don't do this! It'll wreck your knees, and puts a lot of strain on the drive train. You need to spin, spin, spin.
You do want to push back into the seat, rather than pull on the bars though. You'll probably find this unintuitive at first. Finger-light touch on the bars when climbing.
You won't have the right leg muscles for several hundred miles. It'll be slow, and it'll hurt.
It's a trike, so you can climb as slowly as you need. Think tortoise and hare.
It's also going to be some 10% slower than an equivalent two-wheeler on account of the extra rolling resistance.
A tadpole recumbent is completely intuitive to steer, unlike an upright trike. It'll corner more sharply than a bike, and it'll require constant bar input to compensate for the camber of the road. You can proceed dead slow through narrow gaps a bicyclist would have to dismount for, as you don't wobble to stay upright.
If you overcook it on a corner, it'll roll. You'll get some warning as the wheel starts to lift, though. Leaning helps.
There's bugger all weight over the back wheel. It will lose traction easily on slippery surfaces, especially if you're in a low gear.
You've got more work to do to evade the fairy. Three wheel tracks make dodging hazards harder than one. Aim for debris or potholes to pass under your feet, and they'll go between the wheels.
When wheeling it around, pick it up by the rear rack / wheel, and drag it along backwards. The steering will follow.
What do I wear? usual bike kit? or maybe not the padded shorts?
Normal bike kit works well for me. Padding is mostly harmless, but may rub the insides of your legs on long rides.
Anything placed in back pockets will either end up squished, with running ink, or cause bruises. Mountain bike jerseys may be a better choice.
Pockets on baggy shorts should be used with caution, unless they have zips. Gravity is against them. And baggy shorts are best used with something to stop the beasties flying up the leg. DAHIKT.
Change the pedals and use normal cleated shoes, or what?
Yes. It's impossible to have a clipless moment on a trike, whereas flat pedals require constant muscle tension to keep feet in place in the recumbent position. It's also a safety thing: If your feet slip off the pedals, the trike can run over your leg.
How do you carry kit such as overnight gear etc?
The usual way - panniers, rack bag, etc.
There's the additional option of hanging bags from (or strapping things to) the back of the seat.
Bumbags are useful. As are those fishing/photography jackets with millions of pockets and a mesh back.
An inverted rucksack/camelback isn't unknown, but will further impede your ability to dissipate heat (the seat already reducing your back's ability to breathe).
Am I likely to get it on a train, or indeed into a Travelodge? Is it worth removing wheels, or does that make it harder??
I believe this one doesn't fold. In which case, you might be able to get it on some commuter type train services outside peak hours if you're really lucky, but don't count on it. You can forget about dangly bike spaces and the like.
If you completely dismantle it and put it in a bag, it will become luggage.
No idea about Travelodge.
