About the rod, the 6011 are what I use on a regular basis as my welder is crap and thats all it is rated for.
The only downfall of using 6011 (I havent used 6018 so no comment) is splatter and also it can be hard to start the weld with it.
For some reason it almost seems as though the rod needs to get warmed up before it works well same as 6013, (this is just an observation not a fact).
And trying to warm up the rod is difficult, time consumming and also draws alot of power (I feel that two 12V batteries would have a hard time doing this).
If possible I would use a 7018 or even the 6018 if you can 7024 is really nice, its my favorite, or something like that, It has alot of slag but it produces a clean, deep and quick weld.
I would keep a welder at base camp and a generator.
If it so happens that a driver breaks down and they cannot make it back, send someone to get the welder and generator.
As for the helmet, pick up a set of welding goggles.
They allow you to keep them on but also flip up so you can see, plus they are small and lightweight.
They are handy for under a vehicle as they don't get snagged on things.
I have never thought about having a welder handy for trips, good idea