I happened to be viewing a doco on Scotland last evening that showcased the Glen. Presuming that there are boat places you could launch from then what a fabulous wee cruise that would make. You'd want to rug up though. From what I saw it is a very popular spot in summer and bloody cold in winter.
Wayfarer would be fine but I wonder if you could hire a Drascombe ?
Bit more space than a Wayfarer. You can also rig a boom tent and kip on board in a pinch, if the weather turns really foul.