What is the best route to take from Geneva airport to Murren?
The 10:01, 11:01, etc. departures from the Geneva airport connect better with the hourly trains from Interlaken Ost to Lauterbrunnen and on up to Mürren. They can purchase tickets for the whole journey before boarding at Geneva airport. No reservations are necessary on these trains. They are possible on the IC train from Bern to Interlaken, but not compulsory.
Assuming that by "best" you mean the fastest and most convenient, then that would be via Bern. It is a journey of 3.5 hours with 3 train changes, at Bern, Interlaken Ost, and Lauterbrunnen. There, you board the cablecar and ride up to Grutschalp, where you take another train the short distance to Mürren. You can also go by the longer and sloer scenice Golden Pass route, over the mountains past Gstaad, and other small towns, but that takes 5 1/4 hours and 5 train changes. You can see the routes and fares on the Swiss train website, www.rail.ch
Dawn, I usually consider "best" to refer to shortest travel time with fewest changes. The trip from Geneva Airport is fairly easy, but train choices will vary depending on what time you'll be arriving there. For example, there's a train departing at 10:36, arriving Interlaken Ost at 13:28 (time 2H:52M, one change at Bern. reservations compulsory but provided with P-P ticket). When you arrive at Interlaken Ost (east), you'll transfer to the small Berner Oberland train for the trip to Lauterbrunnen (~20 minutes). From there you have two choices to reach Mürren: 1.) Walk across the street and take the Cable Car to Grütschalp, where you'll transfer to the small Bergbahn mountain railway. That will take you directly to Mürren. The train arrives in the "basement" of the station, so walk upstairs and then out to the small "main street". 2.) Walk across the street and transfer to the Post Bus (bright yellow, you can't miss it), for the short (~20 minute) trip to Stechelberg. Once there you'll transfer to the Cable Car to Gimmelwald (have your Camera ready as the ride is spectacular!). When you arrive at Gimmelwald, walk across the platform and board the next Cable Car going uphill. That will drop you in Mürren at the opposite end of town from the rail station. When you arrive at Interlaken Ost, you can purchase a ticket from there to Mürren. If there's a queue, you'll have to "take a number", but the line moves quickly. The ticket will include all modes of transport. Happy travels!
No matter your route, it is a spectacular sight once you arrive up there! Have a great trip.
Thank you so much everyone for the helpful information! I am so excited!!!!
Dawn