Hope you have a wonderful honeymoon. You could always split your car hire and have a convertible for the coast road and one of the others for the rest of the holiday.

Vegas has a central transportation hub where all the car hire companies are located and the shuttles are outside the airport and run approx every 5 minutes. When we were in Vegas we caught the shuttle to our hotel and picked a car up from the Bellagio opposite. The public transport in Vegas is cheap and you can get a 24 hour ticket for $7 which covers the strip and residential areas so you can get up to Freemont Street and see the light show.