Support along the route is important whether you are walking or cycling.
As the Hebridean Way cycling (and walking routes) are linear, the question of how do I get back with my bike to the start? The most simple option is to leave your vehicle in Oban and take the ferry to Castlebay. and use the bike transfer services who will take you (and your bike) back to Castlebay. Bespoke Bicycle Hebrides and HebShuttle all provide this service. And if you are unfortunate to run into trouble with your bike, both these companies offer a bike repair service.
On the Lewis and Harris part of the Hebridean Way walking route you can get dropped off at your location point each day and picked up and taken back to accommodation in Stornoway with Walk the Herbidean Way.
And when you reach the end of the Hebridean Way cycle route in Ness, pop into Sporsnis for that all important shower and freshen up.