Would you mind elaborating a little on your workflow / apps used here please?
There's really not much to it.
I keep computer science/math-related PDFs in Dropbox, copy them to GoodReader (I've started experimenting a bit with other PDF apps, but GoodReader has been my go to for years now), and occasionally use Apple Pencil to mark them up as I read them. I don't save them back to Dropbox for future review; GoodReader is effectively its own island in that regard.
For GPS, I use Gaia GPS to create routes, often with Apple Maps and/or Google Maps running in split screen.
If you have specific questions, I can address them, but none of it is particularly formal.
I also use it to create routes for road trips for my Jeep club: it's really nice to have my GPS app and a satellite view side by side as I look for interesting back roads.
In short: I bought a Ferrari and use it like a Civic.