Contrary to rumours, we haven't left yet!!!! It's tomorrow :^)
I think the travelling part of what you've set yourself is do-able Harv. (Though Pebs is right that the Ullapool to the Orkney ferry is gonna take longer than you'd think by just looking at the map.)
Personally, I'd not try to do Lewis AND Orkney in as short a trip and agree with peeps that you'll not realy be able to do them justice. I've not been to Orkney yet, but was on Lewis for 2 full days and 2 half days - so, effectively 3 days. We NEARLY saw everything we wanted to, but not quite.
When me & John went to Lewis, we left Leeds at around 9.30am. We stopped at Killin by Loch Tay, getting there around 2pm. (We did stay there for a full day too, but that's by-the-by). From memory, we left Killin for Ullapool around 9am I think and via a brief stop at Corrimony and without busting our asses, reached Ullapool around 4 or 5pm - mighta bin a bit earlier. But then we overnighted at Ullapool.
On the way back, we again overnighted at Ullapool and set off around 8am, but the timescales from this part of the trip are a bit off....
The plan was to just drive straight to Leeds, but we broke down & were taken to a place near Inverness on the back of a breakdown truck. Almost ubelievably, the garage they took as to was NEXT DOOR TO CLAVA CAIRNS!!!!!!
So while they worked on the car we were able to have a look at them (we'd both been before) and a cuppla the other nearby cairns. They couldn't fix the car though, so it was back on the truck and we arrived (trucked-up) in Leds at around 10.30pm....
For Orkney, we're planning on leaving Leeds at 6am. We're overnighting at Helmsdale in Sutherland - not THAT far from Scrabster, but it'll take all day. A lot of peeps reckon it's a bit afr for one day, but we both drive & both LOVE roadtrips. Ferry to Orkney mainland around midday.
Then return journey is the same in reverse, except we're going back from Helmsdale to Oxford rather than Leeds, so it's even further. And we have the added pressure of needing to be in Coventry on the way back not long after 7.30pm on the way back, as we've got tickets to see Jeff Beck!!!!! This un's a tall order, but do-able I reckon (esp as we can always sleep in the back of the car when the other one's driving).
So.... If you REALLY wanna go ferrit, I'd go somewhere MUCH further towards Ullapool than Penrith is (!) - you can go to the Cumbrian sites anytime!!!! Somewhere around Glasgow. Next day you'll deffo be in time to get the last ferry over.
And if you REALLY wanna push it, I'd stay another day on Orkney, getting the last ferry and staying somewhere RIGHT up north - near Thurso JoG etc - and leave EARLY the next day to drive home in ONE day. You'll be knackered but there's 2 of you driving and you'll be HOME at the end of it....
(But like I say, I'd not try to do Lewis & Orkney in one trip!)
Good luck to you and us! We'll need it!!!! (Will report back in a week & a bit!!!!!)
Seeya!!!
love
Moth
