San Cristobal is the eastern-most inhabited island of the archipelago, and one of the oldest. The center faces shipwreck bay and the hundreds of sealions that make this home. In terms of “tourism factors”, I would say that San Cristobal is in the middle: not too small so as to always have places to walk but not so large that it can be a bit overwhelming.
You can either fly from the mainland to San Cristobal, or Santa Cruz, and I would honestly recommend starting in San Cristobal, but that choice is yours of course.
Oh, and travelers will either do sea-based travel, or land-based. Quite honestly, after all is said and done, the prices are probably the same, in the grand scheme of things, so it really depends on what you want: as someone who likes to walk, explore, and see cultures, land-based was best for me, but you, dear reader, may want to be on a boat.

Nites
The Hotel Indigo (https://www.ihg.com/hotelindigo/hotels/us/en/puerto-baquerizo-moreno/gpspb/hoteldetail/rooms) is a gorgeous property with every detail given the utmost attention. They will proudly tell you that they are the only property in San Cristobal, and quite possibly the whole of the archipelago, with an elevator which is a nice touch for tired travelers not looking forward to stairs. There are rooms facing directly toward Shipwreck Bay, but rooms with a “partial view”, are cheaper and just as gorgeous. If your budget allows, I would avoid rooms facing away from the water, if you can.

Another option that I seriously considered is Golden Bay Galapagos (https://goldenbay.com.ec/) but they had no availability even when trying to book well in advance.
Bites
If I only had one night in San Cristobal, I would go to Midori Sushi (https://midorigalapagos.com/). The menu is gorgeous and the “green roles” for this vegetarian were out of this world. Situated in the town center, just like everything else, it’s an easy walk, with a stunning second floor terrace that looks over the bay. As with all restaurants in the Galapagos, there is no ac, but when you have an ocean breeze and the sun has set, it really can’t be much better.
I somehow can’t seem to travel and not crave pasta so if you’re like me, I would encourage you to go to Giuseppe’s restaurant. There is no website as of this writing, but they are on social. At the end of the strip, if you will, they had a wonderful selection of pastas, pizzas, and your go-to meat and fish dishes. The staff were attentive, but not intrusive, and sitting outside along the street brought back memories of sitting outside in Roma.
A third option that we tried, which wasn’t as vegetarian friendly as they professed, is Pahoe (no website but, again, on social). This place was packed every night we walked by so the food has to be good. Unfortunately for us, what we saw as vegetarian options wasn’t available, so our choices were limited. Don’t get me wrong, I knew that the options would be limited across the Galapagos given the location of the archipelago and the heavy influence of fishing, we were just disappointed that what we proposed wasn’t available.
Sites
Everything you will read will tell you that you have to do a 360 tour, and they are right. Having the opportunity to boat around the entirety of the island is just magical. Add to this the chance to snorkel, try and see blue footed boobies and red footed boobies at Punta Pit is inspiring. When you consider that 98% of the archipelago is protected parkland, being able to see this – which you cannot do on any other island – is both humbling and inspiring.
There are places that can be booked in advance, or you can take your chances and book when you are on San Cristobal. As a planner, that was a chance I wasn’t willing to take.
For the walking enthusiast, there are paths but north and south of the center that I encourage you to consider. The path to the north will lead you to lookout points over the ocean that are truly breathtaking. If you head toward Baliza de Tijeretas and follow the marked paths, you will be amazed at where you can go and what you will see.
To the south, in the direction of the airport, is another path that will take you to a somewhat secluded beach, La Loberia. Don’t be alarmed when the path turns into a road right by the airport, and there’s an armed guard along the way: just keep walking and then walk along the beach for a surprise that doesn’t appear to be that frequently visited.
And finally, a note to my readers: it’s always difficult to determine how many days you need somewhere, and San Cristobal is no different. Personally, I think two full days, and therefore three nights, is perfect. If you allow one day for a 360 tour, and another for hiking, you’ll be set. Of course, if hiking isn’t your thing, then I would just leave one full day for your 360 tour.