Is it possible to make sims visit Bridgeport without moving out from Sunset Valley? Like it was in The Sims 2 Nightlife.

No your Sim has to live in Bridgeport in order visit Bridgeport. If you check My Sims 3 Blog, Spring4Sims or FreeSimsFinds there are few updated for LN versions of Riverview Sunset Valley and Twinbrook that have high rise apartments, apartments and night clubs for Late Night and your game will automatically spawn vamps and butlers and bartenders etc . Your other possible choice is to save your current Sim to the library and move them to Bridgeport

I can't find those versions for Sunset Valley, could you give a link?

Sunset Valley has not been redone yet however; Riverview has been redone at Sims TR- http://www.simstr.com/gifts/index.php/topic,4990.0.html

Thanks

Do I need the original Riverview for this? Or CAW?

It will be possible, soon I hope. Im in the middle of making a version of Bridgeport which will be usable as a Vacation World. Unfortunately, its taking a bit more time than I expected, as my PC doesn't like CAW very much. The down side is that one of the vacation worlds (probably France, as I dont like France anyway) will be unusable once its installed.