Embajada Universal is a perfect, truly "away from it all" experience, but it's not hard to get to at all. An easy taxi ride from Chetumal airport, bus station, or the new Tren Maya station (which is how we went) took us to the dock, where a boat (lancha) picked us up and took us across the lake (Laguna Milagros). Beautiful, quiet, no other boats or people around. A few minutes on the boat, and you're there!
Don't be fooled by the rustic look of the wooden cabanas--the beds are super comfortable, and the sheets and pillows (I am very pillow-picky) are as good or better than some I've had at properties up in Tulum that are 4-5x the cost. Most of the cabanas are "garden view", lined up in a row with little privacy fences, but there are two king cabanas and one two story cabana that are right on the water and have direct water access. The big one has three single beds on the lower floor (with a bathroom and a very cool shower), and then upstairs is a king bed and another single with another bathroom. These two floors can be locked off from one another and rented separately, or together, for a family or friends, and is the one I want for my next trip! Oh, it has a roof deck as well, for looking at the stars or soaking up the sun. The stars, by the way, are awesome here, as there is almost no light pollution at all.
There's a pool, kayaks, and paddleboards, with some very comfy swing beds along the dock with really good shade for those of us who are sun-careful. Open to the pool and overlooking everything is the restaurant with a full bar. Everything is very casual, very barefoot. Swimming/kayaking is the main activity, but they also have a firepit and a list of holistic activities to choose from.
Embajada has wi-fi, so one could reasonably work from there, but it feels more like the kind of place where you should lock all that stuff away and go for a swim in the lagoon, or just gaze off across the water. If you're into birding, there seemed to be quite a few different kinds flitting around.
One note about getting there: we took the train down from Tulum (which was a fun adventure, very comfortable, and about 3 hours, which is about the same as driving or taking the bus but you can walk around and get snacks/drinks on board), but the train station in Chetumal doesn't have taxis right there, so try to have your transportation arranged in advance. We did not, so we walked off the station property, turned left and down a few blocks to where taxis were gathered. Easy enough, but better to have it set up in advance. I think the taxi to the lancha dock was like 200 pesos. The property will send you a map. Huay Pix is also fairly close to Bacalar, maybe 20 minutes or so, nice proximity to combine two different kinds of stays, which is exactly what I did.
Highly recommend venturing south from Tulum now that the new airport there makes it a lot easier than it would have been from Cancun, and the train even makes it possible to do the trip without renting a car. I ended up taking the bus back up to Tulum, and that was also very comfortable, though the train was nicer and allowed getting up and walking around, which you really can't do on a bus.
US