Would love some advice about the best way to travel from Venice to Slovenia. We are staying in the San Marco area of Venice and I guess there is Uber or buses available to get to a train station and then on to Ljublijana?

Venice does not have Uber or buses, it is surrounded by a lagoon. Use vaparetto (cheaper) or water taxi (more money) to Santa Lucia train station.

Welcome, jjude! You can take the water bus (vap) or water taxi to Piazzale Roma.

Please do double check at your hotel for water buses and taxis to the Piazzale Roma. I have no first hand info but look here also

https://www.rome2rio.com/s/Venice/Ljubljana

There are about 5 daily bus connections from Venezia Mestre resp Tronchetto, 2 trains via Trieste and 1 train via Gorizia (with railway station cheange).
Moore connections from Venice airport and Trieste Autostazione.

Thanks for the information!

rome2rio.com

See https://www.seat61.com/trains-and-ro...a-by-train.htm

I'd spend a few hours in Trieste if you can! One of Italy's most under-rated cities. The Venice-Trieste regional train runs every hour.

I know we sort of talked you into visiting Venice . . . but maybe you need to read up some -- a guidebook or on-line. There are no taxis, ubers, cars, buses, motorbikes, nor even bicycles. Cars are not allowed (even if there was room for them).

SMILE!! yes and glad you did, can hardly wait! Now it is right to Dubrovnik by plane after 4 nights in Venice as there was no reasonable way to get out of Slovenia!

"there was no reasonable way to get out of Slovenia!
Really?
There are trains and buses from Ljubljana to Rijeka and to Zagreb and tons of buses from these places to Dubrovnik
There are trains from Ljubljana via Zagreb to Spllit.
There are 3 daily direct flights from Zagreb to Dubrovnik.
There are ferriy connections from Rijeka via Mali Losinj to Zadar and from Split via Hvar - Korcula to Dubrovnik

I used Omio and RiotoRome and the only bus connections to Dubrovnik were overnight and long. No trains. I failed to mention perhaps that through all these travels, our end point was always Dubrovnik where we will meet family. Thanks for the information, though.