I’m trying to cross a hag with a troll for story reasons.  I’m thinking I’ll give the Green Hag stats a boost by adding more physical strength, constitution, and the Regeneration ability, plus a few flavor things like rubbery green skin, more height, etc.  The trouble is that I’ve been trying for four days to calculate the new CR of my Trag, according to the DMG guidelines, without getting anywhere.  Does anybody have any insights?  Ideas and advice are greatly appreciated!

I mean do you have the statblock made or are you asking what CR it should be for something you haven't made. I can calculate the CR if you can show me the statblock.

I’m using the Green Hag stat block, with some variations:

Strength goes from 18 to 20, Constitution goes from 16 to 20, Wisdom goes from 14 to 18, Intelligence goes from 13 to 14.

Plus, she gains the Keen Smell trait, the Regeneration trait, and the Loathsome Limbs variant trait.

I will also be giving her more spells, since the spells given to green hags are somewhat lackluster.   She’s a level 11 spellcaster, with 26 spells known, from the wizard spell list.  These spells will require material components, unlike her innate spellcasting cantrips.  I haven’t yet decided which spells to give her.

Well,figure those spells out first (I would focus on enchantment/illusion ones and not give her a single fire or acid spell)Because those are gonna have a big impact

Put for starters, I would push her cr up 1 or 2,the regeneration makes her far harder to kill,and the increased stats bring up her damage output a small amount.The loathsome limbs also adds some power but not much.