Myself and a fue others pritty much live on the ridgeway and salisbury plains. Been most places on it.
At the moment the ridgeway is closed due to Ramblers complaints.
There are day treks on and around the plains, mostly organised by other forums or groups but to be honest there is no problem with going on your own.
I used to go on my own, just look out for the red flags. If its red you are about to drive in to a live shelled area and thats generaly not good. The terrain varys. Ive done sections on road tyres, not alot of effort es needed on the flat but if you have AT or MT you have more controll and safty. The plain has mud and ruts in abundant, hill climbs and decents, water crossings and axle twisters. If you are sensible and read the ground you can safely go from one side of the plain to the other on standard tires, but if you go looking for Tank Bogs you will just belly out.
One thing i will point out is that the tank WATER crossing is DEEP. I impatiently drove in once in my Terracan and with the vehicle level the water was over the bonet.
It sounds silly but dont take or fire off any flares or flare guns. And if you see any red or orage flares on the ground smoking near your location evacuate the area as fast as possible.
Due to a busy financial month i wont be going back untill end of april. But if you are still looking to go around that time ill go with you
Give me a PM if you are still looking to go after April.
Jason