Trying to help a friend with route planning (tour of a few days, via Bath to Cirencester area).
On various route planners, we keep getting the route suggestion for Grittleton/Crudwell bit of the Fosse Way as the best route.
I presume this is some kind of rough old bridleway in modern times, ignoring any fleeting sight of marching Roman ghosts.
Are you talking about the stretch of Fosse Way which runs from approx the southern boundary of the Cotswold Airport in a southwesterly direction, crossing the B4014 at ST 91500 90929 then the B4040 at ST 89325 87649 and thence to the M4 underpass, near Grittleton?
If so, I have ridden the entire length of it - and further - a few years ago, but on a pony not a bike. On Jack it was disappointing in a way - I'd've done better to have harnessed him to his cart - so that will tell you that it is a byway not an actual bridleway. In fact it is designated as a Byway Open To All Traffic, and much of it was what I would call semi- or roughly tarmacked, although it was breaking up in places. There were a few muddy spots, mostly carried on to the Fosse Way by 4WDs I think (see later) - but it had been a very wet spring - and a couple of large puddles which Jack objected to by tiptoeing round the edges (don't blame him - who know what dragons and seasnakes were in that muddy water!) and there were IIRC two fords, both of which had footbridges. At some of the spots where the Fosse Way intersected with minor roads, there was considerable fly-tipping, pretty hideous stuff really, mattress springs all over the pathway and the like - but those were isolated, and I got the impression that they were cleared up pretty quickly as it clearly wasn't very
old junk - and some of the actual real bridleways (not Byways) which intersected with the Fosse Way looked as if they'd been (illegally) heavily used by 4WDs; at those points I was very glad for the relentless tarmac and gravelly bits under Jack's hooves! The worst parts of the Fosse Way were what I'd call farm-track surface, and the best parts were smooth tarmac.
As a bike route I think a decent hybrid/tourer would be fine especially after a dry spell. Not smooth riding, and be prepared for some discomfort/gravel/potholes. Widthwise there's absolutely no issue with panniers - it's plenty wide enough for a (small) horse-drawn vehicle. I don't remember any gates or open fields; the whole route was either fenced or hedged, and often ditched, too. As I said it was actually a disappointment to me on a horse as I never once got out of a trot and I'd been hoping for a few good gallops; my mistake in route finding as on the way back by a different route there were plenty. There will be horse riders using it of course - but not many, as we usually prefer to keep off tarmac for a host of reasons including the health and wellbeing of the horse - so if the cyclist is really horse-phobic I don't know what to suggest as the quiet roads round there will have horse riders using them too, at similar or greater rates, in order to reach 'proper' bridleways … Someone who is horse-phobic had better keep to the busy roads perhaps.
I did a lot of riding (horse) in that area a few years ago. It's nice, but not as nice as Herefordshire and Shropshire!
Hope that helps.