Travel from Rome to Praiano

Praiano has no ferry so your options are bus or driver
Train to Salerno then bus or hire a driver ( you’ll need a van)

We used this company for transfers in the area
They might be able to help you
https://www.topexcursionsorrento.com/?portal_referer_id=46

ETA
To save $$ you could fast train to Salerno then ferry to Amalfi town
Hire a driver from Amalfi to Praiano

This is a situation in which you really need to define for us what "best" means to you. Is it fastest? cheapest? most comfortable? most scenic?

The train is the fastest way to get near the Amalfi Coast but not to the Amalfi Coast. There are no trains on the Amalfi coast. You have the option of a very expensive private driver to take you door to door or some combination of the following:

• Fast train to Naples
• Fast or regular train all the way to Salerno
• Crowded suburban train that looks like a subway from Naples to Sorrento
• Public bus from Sorrento or Salerno to Praiano
• Boat from Sorrento or Salerno but I think only as far as Positano or Amalfi
• Taxi from anywhere you choose to give up on public transportation to Praiano.

To be sure, these pics represent the town accurately.

https://iowagirleats.com/life-on-the-mediterranean-coast/