Hi ..our day went like this...
Mum got wired up ECG done ,blood pressure, blood taken and canulla (sp) put in hand .We then went back in waiting room to wait for DR.
Next stage was the injection again wired up for and ECG going for the whole time and very well monitored.
Back into waiting area again to have the food that I did not bring but vending machine outside!
Then the scan which was about 1 hour later...I think you have to wait alt least 40 mins + for the injection to do what it is suppose to do . (said there was a lot of waiting involved !)
Wired up again for the scan (the sticky things are kept on from the start ..so it is just attaching the wires/leads).
Scan and ECG to music of your choice
I am smiling now because they ask mum what music she liked...she was getting a bit flustered now but said Tina Turner...Simply the best.
I burst out laughing and said how was she going to lie still listening to that ...she always bops around to it !!! We settled on a bit of classical and whale music!!
I stayed with her in the room the whole time and she had a dribbely snooze!
We then waited again for them to check the images which were good so no 2nd appointment.
No treadmill,but then I suppose it depends what you are getting tested/checked for .
Mum is 74 so we did not question the young children bit,so can't help you there sorry. and I obviously look far to old for even pregnancy to be querried !! 
We were there well over 3 hours ..nearly 4 but it went ok and smoothly.
Mum coped really well with the tea/coffee thing. She planned her few days in advance so she avoided being in a situation where t/c was on offer ..Ie she became a recluse and did not meet her friend for shopping and stuff.!!
Her first cup of tea after was funny though! We had one before leaving the hospital and "it went straight to her head" !! It is the only way to describe it .It was as if she had had quite a few glasses of wine !
It was half relief that it was all over and a massive tea high !!
She came home and I made her another cup of tea and the she had a lie down for a bit ,but that was her at 74 and finds all DR's appointments overwhelming as she does not always listen understand what is going on.
Ask me more if there is something else that I have not said .