Nick,
Generally, up here,March I would say would be about right -- but please don't shoot the messenger
I have been working away from home on the west coast for more years than I care to remember
The thing is, the weather up here can change so much in the blink of an eye, seriously, I have been working on Skye where we had the four seasons in one day. It is a very big small big Island if you know what I mean
Unlike your part of the world, you have pretty much perma frost. Up here it is bloody cold in the winter, but the sun comes up, partially melts the cold stuff and you think that would be it --- but no.
Major risks to me, whether it be 4 wheels or 2 is driving/riding close to forest areas.
Sun hits the open areas, ignores the tree overhangs, black ice on a tree laden bend -- guess what - you are in the ditch. Also, the main thing that makes me keek me pants is a deer jumping out of said wooded area on black ice, not good. Trust me , I know
I have been there on so many occasions on 4 wheels, but then again I wouldn't necessarily go that fast on two
Makes me laugh when I here weather reports from , I guess our central belt cousins --- " there will be ice on all untreated glens " FFS , we are all glens up here, the only priority gritting goes to trunk roads and bus routes, the rest, well fend for yersel Johhny
To conclude Nick, if you fancy a blast up North, send me a pm, I can go through where you want to go at that time of year. We have several civils contracts over the West Coast and North, I can give you a more detailed forecast based on local knowledge if you wish to proceed.
All the best
Slainte