There's quite an informative faceache page of riders doing/done/planning to do it. Bit of a quagmire up there last weekend for obv reasons lol
eg Latest report from today reports "Day 2 Wantage to Farnham. 101kms. , Trails are almost dry the whole route. Just a couple of slippery bits. "
Ridgeway itself reported as usable with a few puddles to dodge
Not a bad FB group as things go...
https://www.facebook.com/groups/244929213312364
When I rode much of the Ridgeway in April it was mostly dry. To judge by the deep ruts on byway parts and the roughness of bridleway sections, it'd be very slow going if wet. I'd want proper big knobbly tyres to feel secure too. Conti Doublefighters were ok for me, but I did have a few 'moments' on the odd softer/loose patch. I had to lift the bike out of the 'wrong' rut occasionally (there are plenty to choose from on the wider parts: tractors, 4x4s, motorbikes and bicycles - maybe eight ruts of varying width and depth?) and had a low speed topple when I clipped the side of one! Some of the rutted byway parts are very wide though, so if you guess correctly you can ride on the edge and not get trapped between ruts and ditch/hedge etc. Where horses had churned it up and it had set like concrete, it made for some very tough climbs and bone-jarring descents.
Early one morning, I met a young chap on a gravel bike doing the KAW who was not happy 'cos he was:
a) Frozen, having bivvied, (as I did), but without enough warm gear.
b) Unsure of where the next stop for food would be. (On the high and remote part.) Having crossed the Thames and passed though Goring about 45 minutes before, I was able to reassure. (And I had the waterproof Harvey's map.
)
c) On narrow-ish tyres, leading to slower riding and getting cold (see above).
d) ... And his pal had gone off ahead and left him.
I'd be very conservative with working out daily distances and leave a lot of slack, which can always be spent on a leisurely pub/cafe stop.