I did this route a few year back and can recall the astonising beauty of the Isle of Barra in a hard frost (see attached picture). The place was empty at that time of year and I never saw another cyclist (or tourist).
My rough plan is to begin between the 26-28th (roughly, need to plan) at Oban, the ferry to Barra and then to cycle North through the Uists and spending 31st at Berneray hostel. The view over the sea here is amazing. After that on to Stornoway and ferry to Ullapool. Last time I cycled in a day to Inverness and got the train back from there.
It'll probably be cold, perhaps wet, and there's hostel bothies all along the route:
I'd like to camp on Barra as there are some special untouched places where it is ideal. I'm flexible though and these hostels are empty and unstaffed this time of year so can play it by ear.
So if like me you realise it's 2020, all your friends are boring/married and staying in watching Hootenanny, and you're thinking bugger that! - then get onboard!