I was in Chile in 2011 Lys did not have a counter at Santiago airport then . My car was brought to my hotel in Santiago, I spent a few days in he city before I needed the car. I did drop it off at the SAntiago airport and the agent met me in the parking lot and handled the return there. I had no problem with the company they had a good rate and the services were professionally delivered. The rental agent who delivered the car to me did not speak any English and the agent I returned it to had very limited English language skills. I am bilingual so this was not an issue for me.
I think all of the insurance coverage i needed was included in the renatl fee but you should contact them via their web site , they were responsive to inquires and responded promptly -in English . Website: www.lys.cl/
As I recall Santa Cruz was about an hour away from Santiago , a pleasant ride some smaller roads as you approach the town. Overall the roads were generally in in good condition and were well marked . Enjoy and safe travels . Eve