What do you mean starting point? I did all those tours contracted through the hostel where I was staying in San Pedro de Atacama. (But the whole trip was 2.5 weeks: I flew from BA to Santiago and stayed for a few days with friends and went to Valparaiso... then flew up to Calama, shuttle bus 1 hour to Atacama desert. Then from Atacama I did a return overland trip to Salar de Uyuni Bolivia, then 10-hour daytime bus to Salta and flew back from there after).
I stayed at Hostal La Ruca, which I actually wouldn't recommend. The place was OK but the people that worked there were really bad, esp. a negative incident where the older woman (manager?) DEMANDED that I book all the tours through her (so that she could get the commission of course) as I had mentioned that I had done a lot of research myself to compare the tour agencies. She really pressured me into it and even messed up a booking, putting me with another company after I asked her to go with a specific one (she was going to get the commission either way!) and then lying about the group size etc etc... sorry I can't recommend another hostel but I would just go for the cheapest one as they can be pretty expensive there, and I heard from someone I chatted to briefly that he had found a place much cheaper than La Ruca that he was pretty satisfied with.
For the tours in Atacama Desert I stayed there San Pedro de Atacama and did those 3 tours in the 3 days I was there. I knew some people who loved the geysers tour too, people told me not to miss it, but I guess it's not for everyone. There are hot springs to bathe in, but it's nearing 5º outside so it's not the easiest place to get out of the pool. I got headaches from the altitude. I didn't think it was worth the $$ (the most expensive of the 3 tours) it to wake up at 3AM, bear the freezing cold and have a big altitude headache,... but maybe you will like it like many people who go. I did the Salar de Uyuni tour after and we saw some geysers also and had some hot springs to relax in... ok not as many geysers but a geyser is a geyser is a geyser!!!! Maybe ask some travelers who just went when you get there - perhaps it's warmer and not so miserable in another time of year ( I was there in March).
Any other questions let me know!! I love trip planning