Are Golf Savannah Caravans any good offroad

It will of course depend on your definition (or planned surfaces) in terms that you mean of off road.

Corrugated roads and rough tracks.

Jim,
Are you familiar with the type and look/features of the suspension??
Besides build quality, the suspension will largely dictate the performance and ride the van achieves over corrugations. I looked at a Golf van, may have been a 499, not sure, but it had very thick small dia coil springs which to me seemed contrary to suppleness and smooth over corrugations. Maybe ok, but just my assessment of the suspension.
It also had way more ball weight that what I would like, possibly normal for the weight with modern designs but that taxes the vehicle chassis, towbar and rear suspension and axle more. Best to be familiar with some of those features and concepts.

I looked after a friends Golf 499 van after her husband passed away and while the chassis and suspension were of reasonable quality the rest of it wasn't at all suitable for rough road travel.
Golf is actually made by Avan.
The underside of the floor wasn't coated or protected in any way, the wiring was an abomination with a christmas tree of wiring connected to both positive and negative terminals of the battery, some circuits were unfused and those that were had inline fuses in the wiring, no fuse box!
The wiring all consisted of red/black twin individually run to each appliance or light with no protection anywhere they were exposed underneath the van and all stapled individually under the floor!
The first trip of about a 1,000kms mostly on the highway with about ten kms of forestry roads both tyres rubbed through the PLASTIC mudguards and filled the cupboards and storage bin with dirt and water. Avan initially denied any problem until I went with her and pointed out that they had better replace both tyres as well as the mudguards as the inside of the tyres were grooved from the tyres rubbing on the edge of the floor and the mudguard. Avan's cure was to hack a bit of the floor away and stretch the mudguards inwards away from the wheels, the replacements were still PLASTIC.
The solar never worked despite three visits to the dealer until I found the staple that had been put through the wiring and replaced the non functioning solar regulator.
It seemed to keep water out but dust sealing left a lot to be desired and after going over every seam and hole through the floor with sealer it wasn't too bad.
There was no protection for any of the underfloor plumbing wiring etc.
They look the goods but you would be better looking elsewhere.