Well, I used a guide (not the one on this website, some other website which I can't remember) to complete the Ancient City level, and for a few others, but I did all the other ones myself, with the stud cheats on. It took me ages, I started it the day after I got my 360 but never really tried to go for them all until around June last year. It was ok, a few of them were a bit annoying to get but overall quite easy.
Just read you got 1000/1000 for Indiana Jones. How long did that take you and did you find it difficult in any way? Did you do as the achievement guide says (with the cheats and whatnot) or did you do it your own way?