Well, we went with the van. The council's long-stay parking was full, and remained obstinately full, although we and a couple of others cruised in and out for half an hour or so in the hope that a space would come free. In the end we parked on the street up the hill a bit. It was fine - I can see something parked among the bars in the town centre maybe ending up worse for wear after two weeks, but up among the posh houses on the hill I doubt anyone noticed. Ours was not the only van parked for a long period.
And the trip? Cycling northwards from Barra was great - sunshine, tailwinds, fantastic wild camping.... and I think our distinctive tandem gave us a small measure of fame in the islands - people would see it and say "Oh, I think I've heard about you".
And then it all went eerily weather-free on the day we turned south again and headed for Stornoway. Then it started raining....
.... and it poured as we got up and caught the early ferry to Ullapool, with added gales. A rough crossing ensued: curiously there was little take-up breakfast on the ferry. As we waited to disembark, a stevedore wandered along the car deck telling folk that both roads out of Ullapool were closed due to flooding and landslides.
We elected to lurk in Ullapool until the weather had eased off, and, hopefully, we'd get good news about the roads. The town was full of cars and camper vans waiting for the roads to clear. Fortunately no-one had told their occupants about Ullapool's best cafe, so we holed up there for quite some time.... Most of the other cyclists who'd been on the ferry were there too!
Eventually, the rain stopped. We decided to head south and at least look at the blockages - maybe we could wade through where cars couldn't? And the worst that could happen was that we'd have to return to Ullapool.
We waded through three spots where a stream had overflowed a culvert and carried sand, gravel and football sized rocks across the road. Nothing short of a full-on 4WD was going to get through any of them. Cars were stranded between them - they must have been on that stretch of road much of the night, since the streams burst over the road. We got wet feet, but they were wet anyway. And then we got to where the fire brigade had taped off part of the road because they were attempting to recover a big coachbuilt motorhome that had got stranded in a small landslip. Clearly, as it was passing a garden wall, the water built up behind it caused the wall to burst, partly submerging the motorhome in rocks and sand, and stranding a hundred or so other cars behind it, trapped between it and the previous flood/landslip.
We joined the crowd of stranded motorists watching, and when they'd got the motorhome clear and the firefighters had finished messing about with ropes and diggers, we waded through.
We had the rest of the A835 all to ourselves - the best circumstances in which to ride it, I think.
And yes, we made it back to Oban, but no, we didn't ride Bealach na Ba. It was cloudy and wet and there'd have been no view. Another time.