I agree with the decreased weight.
As far as body weight, I do knee pushups because my shoulders can't handle regular ones (actually I've never been able to do a "real" pushup - ok maybe 1-2). I still can't do them regularly, but going to my knees allows me to get them in and I can definitely feel it.
For Pullups - you can use wide-grip lat pulldown (she even suggests that).
Dips - I haven't found a good one for that yet. I still have a hard time with those, but I push through as many as I can.
Crunches - try using an exercise ball, it takes the pressure off a little.
I can't think of anything else right now. Those were just at the top of my head. But definitely try to get the reps in as opposed to the weight. As the weeks go on you'll increase weight and decrease reps. :)
| current weight: 194.4