The track for the route can be found here:
https://ridewithgps.com/routes/1807605
Generally the route is pretty flat, but this is Devon!
The route is all road based, with the middle portion being down country lanes.
There are no major hills, although there are one or two inclines and descents.
The group rides as a group ensuring that all get around, riding at the pace of the slowest rider.
The average speed will vary, according to conditions, but is usually between 14 and 16 mph. Riding in a group is more efficient so if you can currently ride 25 – 30 miles solo at 13 – 15 mph then you will have no problem with the Intro Ride.