I would think long and hard about this mate , it's awrite sane you want to abandon ur life and head too the north of Scotland and live off the land . but in reality it's a hard thing to do , taking on a small croft would cost you a fortune and that's even if you could get one , and how would feed your self , maybe rabbits or fish but you have to learn how too catch them first , and the weather up here can be horrendous mate ,and the midges would drive u mad in the summer time
i would advise you to use the 4 years u have to get plenty experience and skills under your belt before you even attempt this plan ...
i hope you make the rite decision mate and it all works out for you , four years is a long time bud , your life could changed for the better ,,,
aw the best ..