300ft == ~100m so you're about 50% over the max distance of a single cat 5 cable however you can put a switch in the middle and use two 250 ft cables or one 300ft cable and one 200 ft cable and it will work just fine. If this needs to be a low cost option and you are not going to use it much, you could also just run it a 500ft ethernet cable, it will often work even though it is over spec however some network cards won't like it.
If money isn't an option you can always go for fiber, just make sure to protect it from the elements and possible breakage.
If this is an small business solution and you don't have much money to spend and using ethernet with a switch isn't an option due the layout then you can go with a point to point...