Sayulita is the epitome of romantic, sleepy, small town, tropical Mexico. But while it may seem quaint, you can find many modern conveniences here, such as Wi-Fi and ATMs.
There are only a few hotels in Sayulita and rooms are limited. I recommend Hotel Villa Amor. Located a peaceful five minute walk from Sayulita's main plaza, Hotel Villa Amor affords breathtaking views of Sayulita, the beach, and the lush surrounding mountains, as well as the best vantage point to watch the almost nightly summer thunderstorms.
The rooms at Hotel Villa Amor are nicely furnished, but can feel a tad rustic. The locks on the doors are padlocks, but they get the job done. And there are crabs scuttling about on the floor of your room. I found this quite charming after the initial shock wore off.
If you go in summer make sure you book an enclosed room as opposed to the open air rooms because you're going to want the air conditioning. Summers are extremely hot and humid in Sayulita.
The rooms at Hotel Villa Amor are very reasonably priced, especially during the off season, which is in summer. The staff are very friendly and most are fluent in English.
Sayulita is a small, beachside town surrounded by dense, green, jungle. This is a very tropical feeling place. At night, while lightning flickers across the bay, douse yourself with bug spray, sit out on your balcony, and listen to the jungle wake up and come alive around you.