Great Western Coffee Shop

I board a train at Salisbury and go 8 stops on an all stops Cardiff Central service.  I then board a Eastbound HST running booked route, going just 2 stops.  I arrive on platform 1 and make my way to Platform 2 to board a Class 150, travelling to the next city this North-West bound train calls at.  Oh dear, I realise I make a mistake, I need to catch a CrossCountry HST service, so I travel to the nearest station I can catch a XC HST from, heading North to catch the South-bound XC service.  After witnessing an ex London Padd HST terminate and go into nearby sidings to re-appear as a new Padd HST service, my XC service arrives, I avoid the last station I was at, and whizz by 2 further stations before pulling into the next station stop.  I stay on for one more stop though, whizzing through 3 further stations on the way.  I then catch the next available SWT London Waterloo service and I stay on until I reach the first SWT station on the route. 

Where do I finish at?
 
Name all the stations I change trains at?

Bath, Swindon, Gloucester, Cheltenham, Bristol Temple Meads and back to Salisbury.

If you left Salisbury at (say) 08:00, how long would that little lot take?

I'm in agreement with Grhame

Part II then!

I depart Central, after changing trains from nearby Queen Street, and head East on 1Fxx, a Class 158 unit.  I decide to change trains at the next available station 1Fxx calls at to which I can get a direct train to Melksham from.  After a long wait at this 2 platformed station, I board the next service to Melksham, however not alighting at Melksham, but continuing 2 stations further and pulling into a bay platform.  I then catch a East bound HST and get off at the next station this HST could possibly stop at.  I then head North from this station until I reach my trains city terminus.  The train then heads to the sidings North of the station to turn around and form another service back.  I wait a while until another HST pulls in on the same platform, I board this HST and it pulls away, shortly turning of the main line onto a single line track.  I pass many picturesque stations and semaphore signals, then my train pulls into the first of two stations this city has.  I decide to continue my journey and stay on this train though, continuing 3 station stops until my train terminates so I have to exit the train.  I see a FGW Class 150 unit, destination Weymouth and I board this all stops to Weymouth service.  I stay on this train a long time, alighting at its 23rd stop, at a 3 Platforms station.  I wait for a HST which pulls in on Platform 2, and I board, getting of at the next station en-route.  I then get a north-bound XC HST service, and I pass through, non stop, 7 stations before alighting at the next station this XC HST stops at.  I alight and change onto a Class 143 unit from Platform 1, which calls at 9 stations plus one request stop.  I wish to alight at this request stop, one stop before the trains terminus, where I decide to finish my journey and head home as its been a long day!!

Name all the stations I change trains at?

Where did I finish my journey?

How many stations did I see throughout my day?  ( regardless of whether my train stopped there or not )

Which portion of my journey did I stay on a trin the longest?

7 changes you ended up at Chapelton and passed ohhh its too late in the day i will leave that for someone else

oh wait no it cant be.... not enough stops?

I'm thinking that your "three platform station" has four platforms but one's missing its track. And that your journey took place on a Saturday, finishing very late in the day (or did you risk sleeping overnight on the platform at the third most unsafe FGW station?)