i believe a lot people did not participate (or did not have the chance) to play krToS. there are quite a lot of changes since last iCBT2. but i am not sure the same design will be copied from krToS to iToS.
please allowed me to brief a little bit for changes. first, exp curve does not really existed anymore after these period. since then, a few dungeons added, and even missions added for daily tasks.
from last iCBT2, we only had dun50, dun90, dun130, dun160, dun175, dun190 and dun200. if you still remember, we had some serious exp curve in between lv160 to lv175. a few minor exp curve at lv70-lv80 to grind at royal mausoleum construction chapel and lv183-lv187 stuck at no better grinding place.
well, these issues are no longer existed anymore. there are several dungeons added in the between: dun115, dun145, dun217, dun240 and dun260. even they’ve boosted slightly exp for dun160. the more interesting part is, the dungeon party system. at iCBT2, you have to make your own party and then choose for the members. this is outdate style even still valid 
there is 2nd option for it, you do not need to get any party leader or to search for members. the dungeon system will allow you to play with a random party (which will give you +200% exp if you go with random party). however, the dungeon system changed a little bit. you can just do max 5/5 dungeon for any dungeon per day, and no longer 5/5 for each dungeon. oh yea, there are reset dungeon/mission scrolls existed, but it is gifted randomly from the event or compensation. it will reset your dungeon back to 0 so you can do another 5 dungeon runs again.
now, i believe still a lot people do not know what is mission. if you still remember fedimian city, there is a small room on the left bottom corner: its called mercenary post. inside there, you will find a NPC who gives you 5/5 run missions per day (required lv100 to get the response). the same thing you can do like what you do for dungeon runs. select random party option and then wait for the rest party members to join. exp returning is quite good. beside that, you will see another NPC that will give you 5/5 daily quests (also required lv100 to get the response). the reward is exp card (according to your current level).
in the addition, there are 2 selectable birth places at krToS. the original we had in iCBT2 is called klaipeda (blue maps), and the new one you will see later is called orsha (red maps). both of them will eventually joined together when the maps reaching around lv90 to lv110. each of the town warp scroll is a available at both klaipeda/orsha town. you are freely to warp to one another to do the map quests. that means you will obtain more lv1, lv2, lv3, lv4, lv5 exp cards than you had before at iCBT2. therefore, you don’t find anymore exp curve from lv1 to lv160. there is no need to consume the exp cards eagerly and you will grow to lv160 very fast. for lv160-lv175, you need exp cards to get thru these levels. but it has no longer issue because you will have a lot exp cards spared (even i was in lv160, my all quests only completed at lv90 maps). you can still easily continue leveling from lv175 to lv260 without single issue. but the growth will start to get slower and slower.
now, dun260 is a very challenging place. i have not even clear the first floor at krToS but we will together find out how later
with the super grind speed (20-24 hours a day), it will take around 4-5 days for you from lv1 to lv175. if running with normal grind speed (8-10 hours a day), you probably need to take 7-10 days at this part. you may need to spend another 1-2 weeks from lv175 to lv217. another 1-2 weeks from lv217 to lv240. and another 1-2 weeks from lv240 to lv260.
so far, i think we will be good until lv260… my guide that’s all for now. any mistake i stated, please correct me.
oh by the way, choose your stats/skills wisely. the reset potion is very costly at commerical price
thanks.
EDIT (1): thanks to @tehtar mentioned about orsha maps, i will add a little bits for this.