We stopped to visit this mission and surrounding area on our recent trip through the southwest. We had just visited a restored mission, San Xavier del Bac, which is stunning but also feels almost too new for such an old building. Not the case with Tumacacori - it has been preserved but not restored and you get much more of a sense of history as a result. As it was a quiet time, the hostess insisted we take a guided tour but as we couldn't find him, we started on our own and were quickly mesmerized by the mission. We did have a little manual to explain a few things and that would have been sufficient but the guide found us. I am afraid his explanations of the history of the mission took away from the experience for us as he was clearly presented a slanted view of history - one in which the missionaries were a godsend to the indians who had nothing and desperately needed guidance and assistance to survive.
One could easily argue that the missionaries were far from being the best thing to happen to the indians, then or now - so we listened politely and left quickly thereafter. So the lesson here is that this mission is definitely worth a stop - but do it on your own and form your own opinions of what the impact of these missions were for all men and women.