Do you have court ordered visitations which Mom is refusing to allow? If thats the case why are you not seeking sanctions/costs as well?
Generally if the enemy is a no show it makes your side a whole lot easier--but I think it is critical that you use counsel to exploit your tactical advantages!
In short I think you are foolish to go w/o counsel--you want a paid advocate.
You probably won't get full custody --but its possible that child is ordered returned to your jurisdiction (if that was starting point) and you get primay custody and Mom gets visitation--its NOT common --but if Mom is a no show and you have properly stages it you may get most of waht you seek...
I predict if you do not use counsel you come away with only modest/trivial changes in your favor.