Having a hard time working with gpx files, not sure if gpx is for reference only for manual editing in JOSM or if there is a way to use GPS to automate tasks. Any experience here?
Map the Planet!
The best option is usually to load several GPS tracks in JOSM, then manually draw a way over the top of them. Plus use aerial imagery where available. This means you can take an average of the tracks to make it more accurate, and you can ignore any spikes in the GPS traces etc. And you know whether you were walking/cycling/driving at one side of the road, which would make the GPS trace offset from the centre, or if you went off the road and followed a path instead, so you can allow for this.
Note that you can load a GPS track in JOSM, then use the option “Convert to data layer”. Though it is not a good idea to directly upload this to OpenStreetMap. GPS traces usually have many more points than are necessary, so its a good idea to simplify it a bit first. Plus you have to make sure the way is not duplicating any roads etc that have already been mapped, and it is connected to other roads where it should be.