>>1656689assuming I had actually bought the bike in that picture
nothing much really, work with what is already there
maybe add a rack and pannier bags so you can carry some more food and water and clothing with you, + tools and spares
>climbingif this is a concern try lowering the gear ratio
check the cage length of the rear Derailleur
SGS can handle a 34 tooth rear sprocket
it looks like small chain ring at the front is 24 teeth, this is important in calculating drive train capacity
if you do decide to get a different rear cluster of gears bear in mind that only some combinations of gears are available
this is due to how hyperglide sprockets work, they are made as a matching set
id get some foam grips for the handle bar and bar ends, it helps with small vibrations
if the brakes seem insufficient you can get better pads and or put on wider canter levers such as BR-M550 or BR-CX70, just what ever you can get modern brake pads for
going to V brake would Require different brake levers and possibly different shifters depending on how you go about it
that said you probably already have three finger brake levers and they are not really the best
