Are there any other alternatives to the chainglider out there or are they the main player?
What would maintenance look like with a rohloff and chainglider ? I hear you just change rohloff oil every so many miles
What about the chain under the chainglider does that have be regularly looked at ? Do you still get a small amount of dirt/dust etc getting in through small gaps ? It looks a good 95% enclosed from what I’ve seen
There are no alternatives to the Chainglider. The big Dutch chain cases in either metal or plastic are to exposed to damage too be suitable for tourers, the segmented plastic thingies that move with the chain don't work. The only other contender, Utopia-Velo's Country chain case, while under limiting circumstances a theoretically superior option to the Chainglider, is three to four times the price, needs a frame mounting brazed on, is too fragile to go off the road even momentarily, and gains its superb design-silence from rubber parts that must be replaced once year, which the makers assume factory-trained mechanics will do, in short, it is for rich commuters, not tourers. I was lucky mine on my decidedly uncoddled Utopia Kranich lasted a couple of years rather than months.
By the manual, you need to service two parts of your Rohloff, the EXT click box (if you have one -- the bare-wire alternative is called "Internal" and apparently is not serviced except with new cables every now and then) which supposedly needs a shot of grease every 500km, and the gearbox oil which needs changing every year or 3000m/5000km, whichever comes earliest. By going to very high quality Phil's grease in the EXT klickbox I've regularized the klickbox service to the same once a year as the main oil change, without ill effect. Keep to the regulated oil service, especially when your Rohloff is new: your warranty depends on it, and the Rohloff isn't fine machinery, like a watch, it's hefty German agricultural machinery and in the beginning it will knock off tiny bits of metal, which the oil service will remove. You can dip a magnet in the dirty oil to judge the amount of metal ground off.
The cleanest service for a chain in a Chainglider is to let it run on the factory lube for its entire life without any additional oil. My first test ran to 4506km, when I did the gearbox and klickbox services and threw a 50 percent worn chain off because i do only one service a year and I can't be bothered to save a few Euro on a chain at the expense of wearing my expensive sprocket and chainring faster; my bike doesn't even get washed in between but the tiny lanes I ride on are all tarmac and usually clean even in the farmlands so my bike hardly gets dusty except in the harvest season. These days I don't even bother opening the Chainglider to inspect the chain between putting it on and removing it a year later; this year with the COVID restrictions severely cutting cycling, I won't open the Chainglider at all because the chain will go another year for sure. If this worries you, the next cleanest oil is Oil of Rohloff, a chain oil which comes in a small bottle for about a fiver and lasts forever. You put on only a few drops at extended intervals if you run the chain in a Chainglider. Read up on Sheldon Brown about oiling only one edge of the chain so the oil can run in where most needed, which is not on the outside of the chain. Note that I use only KMC 8sp chains, generally derailleur 8sp chains like the X8, because those are the best value for money (there's experience by others of the more expensive KMC "hub gear chains" on the forum here, generally not enthusiastic enough to change my mind about the X8). There's something about the KMC factory lube...
If you search on the forum for "CYA" or EXT you'll come to my experiments on the EXT box. My experiments on running the chain for its entire service life on the factory lube are found by searching for "Chainglider". There are also descriptions by me of experience with all the available chain cases but what you really need to know is that after all that I can recommend only the Chainglider, and a lot of experienced cyclists here have had good luck with it under conditions of varying severity and written on the forum about it. It is probably the one component that would gather the most consensus here; I can think only of Schwalbe tyres and maybe, just maybe, Brooks saddles, which might challenge that status.
Good luck with your bike.