A gps on its own without a map (possibly electronic) is not much use for navigation
I Audaxed for 3 years with exactly that. The old yellow Garmin eTrex H with routes programmed with a routepoint labelled "L@T" or equivalent at each turn. No mapping at all. No breadcrumb trail. Got me 600km across Wales and back for example.
I also did the last 150km of a 200km Audax with no maps displayed on my Edge 705 after some water got into the slot that held the SD card with mapping data. All I had was the pink tracklog for the route and my current position. Took a few turns to get used to but then had no problem following it.
Just a GPS (and no other route info) would be a different prospect though.
I'd be fine with a map though, I spent years poring over them growing up and I'd be quite happy to navigate to somewhere completely new just looking at a map. Being able to look at a map and work out what you should be able to see at any point is a core skill that many people will now be missing.
Them: "We must be here."
Me: "No, we can't be there, otherwise there'd be a church up there on that ridge and there'd be a river over there. We walked past a lake a couple of minutes ago and there's a pub just up the road, of the 3 lakes in this area only one is near a pub and so I'd say we're probably here - if we walk this way for a couple of minutes we should see a junction on the left for Smith's Farm, if we don't see that then we'll stop and re-assess, otherwise we'll be going in the right direction and the footpath will be on the right after a further couple of minutes walk on that same road."
Them: "What? How can you tell that from just looking at a map?"