The free shuttle bus is a must if you want to get around Mammoth Lakes. Sometimes it's just too cold to walk!!
We were quite a walk from Old Mammoth Road where some of the shops and bars were so we took advantage of the shuttle a few times.
The timetables are stuck on the bus stops, and they usually run every half hour or so
We booked flights on the Internet with American Airlines. We kept checking the prices all througout summer 2004 to wait until they were quite reasonable and eventually got a return flight for £380.
Outbound was Manchester-Chicago-Reno,then as we were going to Miami afterwards we then travelled Reno-Dallas Forth Worth-Miami, and finally getting home was direct Miami-Manchester.
To get us from Reno to Mammoth Lakes, we pre-booked a taxi with Stateline Taxi's http://www.statelinetaxi.com/
It was a 3 hour journey and cost $240 dollars each way. You get picked up in an old station wagon a la Chevy Chase in National Lampoon, and their drivers are really friendly and can tell you lots of interesting stuff about the area.
Mammoth lies between LA and Vegas, but is closer to Reno's airport. We flew into Reno and drove the ~150 miles to Mammoth. I remember the drive to be really bland in the beginning, but really beautiful as the trip progressed into the mountains.
It is still within distance of Vegas and LA at ~300 miles each.