Should abandon the limitations of
no Sage stones
no Sinister intent 3/3 accessories
and get a ED shop pet whenever it is possible and if you're lucky enough ( Darkrai posted a list of good pets from ED shop that give a small but nice boost on the other CP discussion thread here.
No ERP used either (all on Item drop and EXP gain)
With your constraints even without using the Red Hero gear (which gives a huge boost due to All skill dmg set effect)
I can rack up 72k with Enchanted magic stone socketing (6% on +8 wep, 2.5%/3% on +7 armour, actually some of the sockets are PB charge or other Offensive sockets that add to Battle Strength, ran out of Enchanted magic stones to finish the set socketing...), which is Entry level for Void weapon farming and Elyanod stone farming
Lv: 21(weapon MP gain on hit 7% ID)
Lv: 22(top and bot PB charge 4%, bot being dmg resist but that does not count towards offensive CP)
Lv: 24 (gloves PB duration 4%)
Lv: 29 (shoes DMG resist again, doesn't count towards CP)
Item Mall OR currently available event dungeon exclusive gear that you can get if you do it daily and Perihart's Tear which you can get from Story line quests, apart Eltrion legend necklace but that one has IDs of DMG resist only so... only MP gain stuff are included to CP.
Preferably critical hit and Deva though I am not sure if I imagined it but Critical hit stat gives more CP than everything else.
If we take Sage stones (which are even in current Event: 1 run for 10, 2 runs for 20 and 3 runs for 30 that's 60 Sage stones)and take only sockets that are above 3% on armour and 6% on weapon, would have Red Hero set parts (2/5) at Lv at least 26+, you should be able to hit at least 95k or 100k (feel like I forgot to mention something...)
However that's only in theory as I have not tested it considering I have 300k+ CP on my Raven by CASUALLY playing and farming stones now and then (or stealing from friends...) for Elyanod set and invested a bit on Upgrade event for +11 Void weapon that is not even stage 15 yet, and I use that to farm up any other stones for other characters (apart Elyanod gear because I'd rather do Story quests for ED and a free 4/4 Elyanod)
Can't gurantee it but, it is highly possible in my opinion.
Also it's possible to grab that +9 Hero weapon which is free on D-day event to help you farm Void weapon which would also increase CP by a bit due to higher ATK/MATK.
Right, forgot to add that AND IF your Hero equips have a good Hero effect that adds to CP (Excluding the Stacking or On Hit/being Hit effects since those don't give you any CP)