Regarding transportation to/from the airport, we took advantage of the National car rental office in Punta Mita on our last trip. Meaning we picked up a car at National in PVR airport and returned it 24 hours later at National in "downtown" Punta Mita (and reverse on the way back). If you don't feel like walking the 2 miles from StR to "downtown" you can take a taxi.

The cost was 40USD pr. day for a full size automatic (Full Size in Mexico = Toyota Corolla), and having a car on the first and last day allowed us to take trips to Sayulita, which was very nice. Driving was OK, the locals seem used to tourist on the road - just watch out for the massive speed bumps !