Check both sprockets. they seldom give trouble and are unlikely to need anything. buy two chains the same brand. not Indian made. Elite are good value as are others. (think HD chains will fit) Running them as a pair means in an emergency you can change a chain in less than five minutes with just a pair of pliers and a screwdriver. Generally I use one a s goingthere chain and regard the spare as a getting home chain. Often this does not get fitted as wont be needed. DO NOT OVERTIGHTEN the chain, the later suspensions are gas and have a longer stroke so it is easy to set them too tight when on the centre stand. you want about an inch play with the bike loaded and on the suspension with you on it. You will need someone to help. Also do not trust the chain adjusters to be correctly marked. put the bike empty on the centre stand and spin the back wheel backwards. check the chain runs freely equidistant from both sides of the rear sprocket. carry a spare clutch/throttle cable sealed in a plastic bag.
DO NOT INCREASE the gearing ratio. it will slow you down anywhere except when going downhill with a following wind on a motorway.
Spare spokes can be fitted on an assembled wheel I have seen it done but never had the need myself. That bike was overloaded, overgeared and hotted up and struggled going up hills whilst mine trundled up them easily. It is worth carrying a spare rim tape to fit if you need to change a tube.
Note also tyre pressures are meant to be lower than is often common for tubeless tyres.

Service your bike and keep all of the tools needed together as your toolkit.

that should do it.