I would definitely start working toward a 4-hour EASY - you can do 3.5 as a transition even. And try to extend her A time slowly as well - maybe even just do 1.75 hours for now. When she starts getting cranky, take her for a walk, put her in the sling, go outside - something calm and relaxing but distracting. That should help lengthen naps as well. Once she starts taking longer naps you'll likely find that she can stay awake longer too and then start heading to 2 hours A tiime.