If she will eat pumpkin, its good at providing bulky fiber. Squash can be used to a lesser degree. Mostly its just getting fluids in them, just like with us.
Will she let you do a pinch test on her back quills? Basically pinch/pull up on her back skin a little bit and see if it snaps back into place of it takes a bit to go back to normal. If it takes a bit she's dehydrated, which could explain the constipation. The longer it takes the more dehydrated she is. If she's dehydrated then we need to figure out if its just from not drinking and how to encourage her to drink more, or if its something else causing it.
How are her eyes doing? One concern I often have when they start to get up during the day if they never have before is if they are seeing really well. If they are developing cataracts they sometimes get confused about when its day/night. With that said, I have had some that just get up during the day as they get older for a snack or to go to the bathroom.