In case you've been living as a hermit for the last 5 years, Gravel riding and Gravel Packing is the 'in thing' currently. Every man and his dog is adding a Gravel Bike to their stable. So, obviously ELSR has jumped on the bandwagon and is milking this trend for all its worth!
East Anglia might not be the most exciting place in the UK to gravel bike, but we have a good selection of bridleways and a very dry climate, which means lots of trails which are rideable almost all year round. There are good train connections from Cambridge to the coast, which gives lots of option e.g. ride out, train back etc.
Our local trails are definitely at the easier end of gravel riding with virtually no technical sections, unlike say The Lake District or Mid Wales. However, they are pretty fast rolling and given how flat the region is, you are able to cover good distances very easily e.g. the Fastest Known Time for the 372 km Rebellion Way is a staggering 13h:30m! See Strava. However, we would recommend a slightly more leisurely approach, e.g. splitting the route over three days and enjoying the scenary.
A very good question! With the current trend of road bikes accepting wider and wider tyres, the difference between modern road bikes and gravel bikes is shrinking. Typically, a gravel bike will take anything up to 55mm tyres with good clearance for mud and / or mudguards. The geometry will be slightly more relaxed (longer wheelbase and slacker head tube angle). This will favour stability over razor sharp handling and make the bike easier to ride over rough terrain. They also tend to have a more upright position e.g. slightly shorter reach and higher stack than road specific frames.
However, the single biggest difference in handling comes from running wider tyres at lower pressures, which make a big difference to how the bike feels on bridleways etc. For our local trails, you won't be pushing the upper bounds of technical riding, so a more road orientated frame with some 35mm tyres will probably be absolutely fine.
If you find gravel ride a bit battering on the wrists or hands, there are some excellent solutions out there e.g. I use a RedShift stem on my Gravel Bike, which makes a huge difference to how rough the trails feel and how far you can ride.
Worth noting that the Rough Stuff Fellowship have been riding (or often carrying) normal road bikes offroad for a very long time e.g. when it was compulsory to smoke a pipe and wear shorts in winter, even for ladies.
Also, mudguards are really not a very good idea when riding off-road, they tend to pack with mud and jam the wheels!
Traditional panniers are so 1980s. Every outdoor company under the sun is now selling soft, strap on luggage for gravel bikes. E.g. for one or two nights B&Bing I use:
If you're using B&Bs, then you only really need a change of clothes for the evening and maybe a spare pair of cycle shorts and a toothbrush. Spare shoes take up most of the space, but it's nice to give your feet a rest and your cycling shoes could easily be wet. If you're camping then you're going to need a lot more kit and be a lot more inventive in how you pack it e.g. see Juliet Elliott's set up.