You may think that sailing and rowing through the Great Glen in varying Highland conditions sounds a bit tame. In which case the Race to Alaska is the raid for you
https://r2ak.com. 750nm from Port Townsend in Washington State, northwards to the next bit of US territory, Ketchikan in Alaska.
There are lots of islands along the route which provide a bit of protection from the west. However, motors and engines are not allowed and there are no support vessels. First prize is US$10,000, second is a set of steak knives. This year's race started early last Thursday and the first two prizes had already been claimed today, just under four days later. Having a modern-rigged multihull with bicycle-type crankshaft propeller(s) seems to be the way to go.
The rest of the fleet is still out there and there have been several withdrawals from the race. Amongst the risks to be encountered and obstacles to be overcome are tidal currents of up to 15kn; gear breakages from sudden squalls and running into submerged logs at high speed; and hypothermia and acute sea sickness. Oh, and if you decide to run ashore for a brief rest, there are grizzly bears. I expect that orcas and whales are a potential hazard too.
Some of us complain about the amount of rowing in Sail Caledonia, especially when the wind dies on Loch Ness, or about the difficult sailing conditions when the wind really picks up. However it's a bit of a doddle by comparison with R2AK. I've done Sail Caledonia four times now and I'm beginning to wonder whether Nessie even exists.