peice of cake, drain the fluid, pull the speedo cable, support the tranny. disconnect the mounts to the body. undo a bunch of nuts pull the cover off, panic when reverse falls on the ground, clean up the surface, install new gasket figure out how reverse goes in, put cover back on, install nuts and torque, reconnect tranny mounts fill tranny, reconnect speedo, go for a drive. then do it again to fix the leak where it is actually coming from.
take the car to the car wash and pressure clean the car, drive it home and look for the leak.
BTW the have a tech article for repairing the first gear here, it will tell you how to open it up.
http://www.pelicanparts.com/techarticles/914_tranny_repair/914_tranny_repair.htm