There are fires up that way and you should check on the day when you want to travel. Thunderbolts Way is doable with a caravan. There is one massive hill to climb after the Barnard River - steep and long with no letup, but once you have done that it is relatively easy. Road is wide and generally well aligned.
We travel regularly from Forster to Tamworth. We tow a 19 ft Avan on a BT50.I like to go over Port Stephens cutting as it saves about an hour going through Walcha. You will need a UHF radio to call trucks before entering the cutting. Takes 6 minutes taking it easy. We came through last weekend and there was some smoke from a nearby fire but haven't heard any more about that. Check NSW Fires near me website.