You can RP the remote farm as a "Hidden Valley" only accessible through your fortress. Heck its one of the few times in the game where you could go nuts with raised earth walls and deep pit. Farm in the pit, keep the walls irregular and as steep as possible, use cultivator 'grass' setting to change the look of the raised walls a bit.

Plus points for doing that on a border between Mountain and Meadows.

Sounds fun :)

PS: Also might need to do that with a Plains/Mountain border as well.