WiFi extension between two cabins 50 ft apart

whats your budget? you have several options. A little depends on the temperature in your area. to hot/cold and outdoor connections will fail quicker or not work at all. 

1. get a outdoor rated extender that is powered over POE. It'll also be able to use that connection to connect another access point to in the cabin. 

2. Get a weather proof enclosure to put an extender in. This would open up the options to more devices. 

3. Spend a little time and bury an underground rated ethernet cable. They're not expensive and they're going to give you the most throughput/reliable connection. They'll also be the cheapest option. (this would be the option I'd use)

4. get a access point that you can add antenna extensions to so you can put them outside the cabin (then you don't need to weather proof the access point. Then simply connect another access point to it via cable in the cabin for broadcasting in the cabin. 

It all comes down to you'll need something external to the cabin to pickup the signal and then run a wire inside the cable to connect another device in the cabin for working on the inside. Or you simple take the time to bury the cable.