You should read more guides and play more games, because there is no one size fits all for jungling. I’m a Kha’zix main as well, so I will attempt to answer some of your questions to the best of my knowledge.
Yes, the minimap is exactly the same in PvP as well, however it only gets updated dependent on your vision. Meaning that if you saw that your golems are up 10 minutes ago and never went back to check, mini map will still show a cursor that they are still up, however if the opposing jungler decided to invade your jungle and take your golems, when you come in the golem camp you will find nothing there even though there was a star in the minimap before! (after seeing that they are gone, the minimap will appropriately show no cursor at that camp anymore).
There are 2 general routes for all junglers unless you are doing something funky.
Route 1: Start at blue golem camp, use smite to kill blue faster/take less damage, then do either wolves OR wraiths, not both, then do red lizard camp (smite should be back off of cooldown at this pt, so use it again!) At this point you can opt to gank bot, gank mid, or continue to farm if neither lanes present an opportunity.
Route 2: Same as 1 but in reverse. Start red, use smite, take either wraits or wolves, not both, then take blue with smite, gank mid or top if the lanes are gankable. Otherwise continue to farm.
Certain champions like Lee Sin and rengar benefit more from Red buff than blue buff since they use no mana, so they opt to use Route 2 more often. Most junglers use route 1 because they are blue buff dependent early game.
You don’t HAVE to gank. If opponents are playing safe, warding and staying close to his tower you will not kill him if you gank. So instead of wasting time with that, go back to farm.
As per your question on what to do if your lanes are not gankable, you can opt to either go back to farming in your own jungle, or go to the enemy jungle, drop some deep wards and start to take his jungle (this is a very high risk high reward move, it can outright win you the game or make you a liability if you are careless).
Counter jungling is a whole different game and you should look up guides on how that is done, when to do it, etc. It is always a good idea however to buy wards, go sneak into the enemy jungle between your routes and ward the enemy red, or enemy blue, or in the bush between the enemy middle inner turret the wraiths. You want to ward these areas because you want to know where the enemy jungler is at all times, it provides safety for all your lanes AND gives you an opportunity to go sneak into the enemy jungle with a buddy and 2v1 the enemy jungler.
As per Kha guides, make sure you are using the updated ones. Back in the day you would evolve Q or E first and max Q first, and never evolve W. However, in light of recent nerfs the modern Kha build focuses on evolving W and maxing W first, evolve Q last (max Q second). Occasionally you can evolve E first if you are ahead and are killing things left and right.