Questions: For those who use GPS mapping, do you also carry paper maps?
To answer your question .... It depends, but usually no. And even pre gpx I didn't usually carry maps. Mind you, that was in Europe and I did a lot of navigating by river or canal. A photograph of a bike map placed regularly along the route could last several days.
I use mapping apps on my phone, either to see where I am and to get local, live info (Google maps), route plotting (cycle.travel, Osmand).
I like a paper map to see the "big picture" which is difficult on a phone. But those maps are invariably poor for trying to plot a route on.
Bear in mind that I rarely have a definitive route in mind when I set off. They also serve a useful (for some) purpose by drawing people towards you if sitting down poring over a map. They are far more sociable than a phone or tablet.
Presuming you have the route already created in RWGPS what information will these maps have that you will need?
Is it just for redundancy? A back up in case of a technology fail? Do you want to be able to wander off course and need the extra information that these maps offer?
Depending on your answers there are probably better, lighter and more useful options.
Any info about the route (accommodation, stores, etc.) can simply be stored in a memo app on your phone or on a mapping app like Google or Osmand.
For redundancy, time to be realistic. If your Garmin fails you still have your phone. If your phone fails you still have your garmin. If both fail you have other problems than just a lost route. In any case, a new phone, Internet connection and you're back in business. Or just buy a map in a store.
Have you tried looking at the downloaded pdfs on your phone? If that works for you you can bring them all with zero weight penalty. Or perhaps you're planning on bringing a tablet?
Perhaps the PDF format doesn't work well so try photographing the map on your phone. A photo might "play" better.
The only disadvantages of using a phone are battery dependence and difficulty in rain.
And (as above) there are people. You can always talk to them! Just remember that drivers always underestimate the distances!

If you are going to take printouts remember that unless using special "paper" or laminating them they will likely need handling with kid gloves and bone dry storage.
Since you have a new gps unit and admit to not being very technically adept (neither am I) I'd encourage you to stress test it (and yourself!) as much as possible.
Try going off course and see what happens.
In an urban area pretend that a road is closed (or totally unsuitable) and see how to get around it.
Try creating a route "on the fly" both online and off.
Create a figure 8 route and see how the unit handles it.
If it has the function to save locations practice using that feature (perhaps for hotels in large urban areas)
Get a handle on battery life. Just how far will 10% get you? 5%? Similarly, how long to charge it?
Can you input an address into it and will it calculate a good, safe route?
The better you know and understand your unit the less stress you will have.
Just a final comment. One of the best pieces of gear I use is a Kindle. Not only am I toting a huge library with me I can also back up important documents, route notes and even maps (quality may vary) on it. For travelling I can download entire wikipedia articles about places. Of course, there's a kindle app for phone and tablet but a separate device is another layer of backup.
Good luck!