Posted October 8th, 2017, 03:38 PM
I just ran through a mock booking, so let me see if I can step you through it. Go to Rome2Rio.com and plug in your origin as Valparaiso and your destination as Santiago. Several options will pop up. Choose the cheap bus option (should be around $4-$10). It will now show you a bus route from Valparaiso to the Pajaritos station in Santiago where it recommends a connection to an airport bus. There are no direct buses from Valparaiso to the airport. Click to open the first leg. It gives you two options - TurBus and BusesRomani. I've only used TurBus, but I'm sure BusesRomani is fine as well. But, TurBus runs every ten minutes vs. once an hour for Romani, so, to me, it's more convenient to use TurBus. If you choose TurBus, click on the link to the TurBus site.
Here's where some knowledge of Spanish would help. If you're like me and know very little Spanish, you may want to open a translator in another tab so you can bounce back and forth.
Plug in your origin as Valparaiso and destination as Santiago. Plug in the date. Click on Solo Ida for one way, and in the drop down, click on tarde for afternoon buses. Click on Comprar. If the first list of buses is too early for your schedule, click on the Forward button (Seguiente) to see later buses. I see several Sunday options that leave from around 7:00 until 8:00 PM and get you into Santiago around 9:00 or so. But, you'll notice that all of these are taking you to the Alameda Bus Station. Recall that originally we were looking at traveling to the Pajaritos station in Santiago, but far more buses connect to Alameda, and it's just as convenient. Personally, I prefer Alameda as it's a good size bus terminal, while Pajaritos looks more like a glorified bus stop to me. But, you still need to get to the airport.
Go back to your Rome2Rio window and go back to the home page. Type in Alameda Santiago as your FROM, and you'll see a drop down option of Estacion Central. Select that. The TO is obviously Santiago Airport. The first option presented should be the cheap $2-$3 bus. Click on the link, and it will show you that Centropuerto operates a bus every 10 minutes from the Alameda Station to the airport. I went to the Centropuerto site, and it appears that buses run until 11:30 PM, 7 days a week.
I'm giving you all of this so that you can verify for yourself that this will work. It's not nearly as complicated as it sounds. Basically, TurBus from Valparaiso to Alameda Station in Santiago, then connect to another bus to the airport. Counting wait time, I would expect that the entire trip would be 2 1/2 - 3 hours max. FYI, the ticket window at Alameda is a little hard to find (at least it was for me). After you come in the front of the building, the ticket window is on the far left. From where the buses park, it will be far right. You can take any bus to the airport - you don't need to specify Centropuerto.
Hope this helps. It may just scare you into taking a $100 taxi, but I hope not. Oh, you will need to take a taxi from the port to the Valparaiso bus station. I believe that was $10-$15 for us.
Let me know if you have any questions. I know nothing about bag storage options.