From reading anecdotes of spotting days in the steam era, I get the impression that the average schoolboy trainspotter was largely restricted to their local area or the distance they could ride a bicycle, with typical pocket money not stretching to trips of any distance unless it was specially saved up. Over the years since then, the possibilities for affordable travel gradually opened up.
I recently dusted off my grimy old trainspotting notebooks after years of storage in the loft. My dad had been a schoolboy trainspotter in the late 1950s (at his local station near Stockport) and he started taking me out on spotting day trips in the mid 1980s when I was seven. Our nearest station was Gillingham (Dorset) so some kind of day trip was required to get anywhere interesting, unless you were happy seeing the same 33s and 50s at Salisbury. I think the geographical limit of our typical day trips roughly corresponded to the sort of distances where you could get a cheap day return. Typical destinations were Southampton, Exeter, Reading, Bristol, Cardiff, London, Bletchley (but strangely we never spent any time at Westbury or Eastleigh - I think I was more focused on spotting passenger stock and had a fixation with the screaming Valenta glamour of the HSTs).
Occasional special travel offers like "Network Days" (on Network SouthEast) and the "Ready Teddy Go" promotions were useful for travelling further afield such as onto the Great Eastern. We made a couple of long-distance trips to do overnighters at Crewe (a sort of birthday treat), but that kind of distance wasn't common. One indicator of this is that it wasn't until the mid 90s that I was able to visit any part of Scotland, by which time a lot of interesting loco-hauled workings (not to mention the entire classes of 26s and 27s) had disappeared. We didn't usually do Rover tickets either, although for one week in the early 90s we did a "Freedom of the South West" which involved consecutive day trips from Gillingham (Dorset) to Devon and Cornwall... the extreme avoidance of overnight accommodation seems a bit eccentric in hindsight! Open Days were a relatively frequent occurrence, taking us to places like Laira, Old Oak Common, Bristol Bath Road (I regret never going to any Tinsley open days).
Strategically located grandparents near Lincoln and Stockport allowed for occasional day trips in those exotic areas of the country during school holidays- I distinctly remember the thrill of being able to see out of the front of 1st generation DMUs in the East Midlands, the bouncy seats of class 304s out of Manchester Piccadilly, visiting places like Crewe, Birmingham, Chesterfield, Doncaster.
Later when I was a student in Manchester (late 90s) my regular haunt was Warrington Bank Quay on a Wednesday afternoon, a very cheap day out from Manchester! To get further afield, I remember taking advantage of some kind of £10 Virgin Trains offer (possibly in connection with RAIL magazine) to do a couple of day trips to Glasgow, when there was an early morning direct train and a late evening return... I remember 158s working it, but also an HST on one trip. Later when I moved to Doncaster (early 2000s) there was a similar early morning / late evening ECML working that allowed a long day out in Glasgow with reasonable fares... combined with a Strathclyde Daytripper ticket it was very useful for spotting Scottish units... and you could even take a boat trip across the Clyde thrown in!
After getting out of the habit of spotting (depressed by the class 66 invasion) my interest switched to trying to explore as many lines as possible, using rovers and day trips and a few short holidays in Scotland / Wales / South Coast. Lately my rail interest tends to be fairly local. I started taking pictures around Doncaster during Covid out of boredom, with the occasional trip to local places like Hatfield & Stainforth / Swinton and recently Church Fenton and Chesterfield... back on the same platform where I'd been over 30 years before watching the trains with my dad.
In faded pencil in an old notebook, a bit of nostalgia - a busy hour of freight (and a couple of light engines) at Chesterfield on 23rd August 1991 - coal and steel and proper engines:
12:15 Down Main - 37110 + steel empties
12:20 Down Main - 47363, 47378 light engine
12:25 Down Goods - 47220 + Distillers CO2 tanks
12:33 Down Main - 37716 + steel empties
12:37 Down Goods - 60022 + steel empties
12:40 Down Main - 58043 + MGR empties
12:45 Up Main - 47463 light engine
12:47 Down Goods - 58045 + MGR empties
13:00 Up Goods - 60001 + MGR coal
13:12 Up Goods - 58016 + MGR coal