What is the best route to commute from Mt Eliza to the city?

Which route you would take would be dependent upon the time you were traveling.
If you were out of peak hour I would go Eastlink and Monash.
This would take about 45 50 minutes.
If it was peak hour Nepean Highway or even Beach Road are good options.
If you like to travel by train get on at Frankston station and relax and enjoy the trip.
Dorothy Alkemade Real Estate Agent and Home Owner Mount Eliza

If traveling via car, the fastest is definitely East Link/Monash Freeway as expected (but not during peak hour traffic). Commuting via East Link to the Monash Freeway is very popular among commuters and is relatively quick. This will also get you directly into the city. Current work on the Monash Freeway is also expected to improve the commute time and reduce congestion.

However, travelling more closely to the bay via train or Nepean Highway can also be popular due to the quality of the drive.

If you are travelling by car, the upcoming Mordialloc Freeway will help the commute. The Mordialloc Freeway will deliver an extension of the existing Mornington Peninsula Link to the Dingley Bypass. This will create a seamless commute from Mt Eliza to Cheltenham via a single Freeway. The Mordialloc Freeway is expected to cut the commute time by at least 10mins which will be beneficial. This will make it the fastest as it currently takes 45-50 mins via Peninsula Link/Nepean Highway. This will be reduced to 35-40 mins with the new Mordialloc Freeway. Once closer to the city, traveling via Beach Road, Marine Parade and Beaconsfield Parade is also really enjoyable as expected traveling near the beach. Or you can travel more quickly and directly via Nepean Highway. Plus, traveling up an down Oliver's Hill makes for a magnificent frequent view (but don't get distraction and be careful when driving). Mt Eliza's leafy reserves also create a stunning scenic sight when traveling through Mt Eliza.

If you wish to travel via train you can take the express service on the way back to Mt Eliza to lessen the time. The government is also proposing a 'Frankston Flyer' which would include a third track between Frankston and Moorabbin to allow for more express services along the rail line and reduce the commute time. The train is definitely more relaxing and you get a few nice glimpses of the bay occasionally because Frankston Line runs along Nepean Highway mostly.

In the future, another optional route will be via Port Phillip Bay into Docklands. Port Phillip Ferries plans to have a ferry service from Frankston to Melbourne, similar to the one from Geelong to Docklands. This would definitely make the commute more appealing and take more traffic off of the roads with more travel options. Port Phillip Ferries also haven't shut down the idea of having a commuter ferry to Mornington as well. Other ferry terminals are also expected along the south-east end of the bay which will further reduce traffic from these areas to ease the commute.

Your best bet is Peninsula link onto Eastlink. You can also use the Monash Freeway, but this route can be very busy.

Where about in Melbourne do you want to commute to?
Myki the public transport pass card takes you every where. Travel all day from Mt Eliza Bus 10 minutes. 50 Minutes to Flinders Street then on and off all trains buses trams.