I currently just keep a text note in obsidian for tracking on the go then manually copy into the proper reports at my desk later. Which is a long way of saying I'm watching this note closely for useful answers.

@Scott just to include you because you responded Did a search and for open source and privacy focused, especially for tech challenged as myself, looks like Firefly III haven't checked these out yet but, gnucash, offline expense tracker and waterfly III which is like firefly. I'm using Libreoffice now for the Excel option and just running with that for now. Going to check out water fly today

Firefly is on my todo list to self host, but not at the top so who knows. Also not sure how well it will work for noting hop to hop mileage while out and about. I'll find out when I get it working.

I don't yet and I don't know how to do that to be honest

Waterfly seems to be the mobile version

Hm, as in fully mobile or a mobile frontend?

I have below average IQ can't answer that honestly lol. From what I read it's a mobile version. From there I don't remember

It looks like it requires that you have a firefly III server for it to talk to.