I have added a poll - and NOT provided an "it depends" because I am asking about a typical or average day out.

Thinking of a typical day out of mine, I might classify an early £2 bus fare into Trowbridge at the start of my day (the 06:32 train being too early and the 09:10 too late) and then £3 for a cup of coffee from the van at Trowbridge station.  Fare of £15 headed for Weymouth, it's a "large" coffee and a cherry a yoghurt flapjack at Westbury as I change trains - let's say another £4.    Even without parking, my costs add up ... and I may include the cost of fish and chips and another coffee in Weymouth during the day, as opposed to a chesse and marmite sandwich and an apple at home.   Numbers *not* checked against current costs - it just seems to melt away and I get shocked when I go into my wallet and realise I have pulled out the last note, or when the credit card bill comes in for the month.

I do know that when I buy my internal pass, that will just be a small part of my spend once I add in accommodation, food, drink, and other ancillaries and it makes the current 25% discount on the pass look trivial in the total picture - but I have a window of opportunity between being retired and being unable to move around on such a trip and I am going to take it, even if it reduces any inheritance I pass on to the kids.

Indeed it depends ... which is why the question asked in the poll says "typical", and looks for the comparative spend on a typical or average day.

I can find you a day trip on which I took guests from overseas to London and then on a tour of the town on a TravelCard, without stopping in to any of the paid attractions but rather noting them to perhaps go back later.   Most of the spend on travel.    But then another - a day trip to Weymouth as part of a FOSS^▸ (Freedom of Severn & Solent rover ticket) 8 out of 15.  Add bus fare to Trowbridge (no suitable connection from Melksham), coffees at Trowbridge and on change of train at Westbury, and you can consider a stop in a restaurant / lounge before the 19:30 return train to Melksham as an extra expense. And most of the spend is not on travel.

Definitely more than half, but in my case it is usually for a cycling trip with food and drink carried from home.

The poll got me thinking about my non travel expenses on a day out so I had a quick review of all the day trips I've had in this calendar year and come up with a very rough figure of just over half the spending being on transport..... mostly rail.  The increase in the rail fare element of my transport costs in the coming year should be partially offset by the bus pass that I've now been the owner of since last week.