Flying to Santiago at the end of the month. Saturday-Saturday. Was thinking about 2 days in the city and the rest somewhere else. Here are my thoughts so far, but would like some help:

We are comfortable taking a flight somewhere to spend 4 days:

Patagonia seems too cold/rainy this time of year, and seems like it would require more preparation than simply taking a flight, showing up, and "winging it".

The North seems interesting and would have better weather this time of year. For 4 days, what would you recommend? Here are our criteria/thoughts:

--Round trip flight from Santiago for under US$500 (ideally under $400)
--Would ideally like to see water and mountains. A rental 4x4 sounds like a good plan. Are 1 way rentals possible? Then perhaps 2 1-way flights as well.
--Peru and/or Bolivia would be ok. For example, seems like from La Paz, we could see Lake Titicaca, the desert in Chile, as well as the ocean via a bunch of driving?

I plan to get a guidebook tomorrow, but thought if anyone had some higher level suggestions to get me on the right track, I could work out the details on my own.

Thanks!