I think this 'making up an exhaust' is a lot more common than you may think. If that one isn't near you, you could just try your local exhaust shop. I'm just back from Norway and there is an incredible company called Biltema. Their shops are like B&Q would be in America. You could park outside a Biltema, go in, buy trolley jacks, spanners, zip guns, a compressor, welder, - all the tools you might ever need to change your exhaust. Then having put the wagon up in the air you could go back in and select all the tubes and clamps and silencers you would need to completely replace the exhaust. Then you could go to the cafe area and have lunch and a superb one at that, far better than Ikea.
If you do fishing you could go back in, buy a small boat and all the fishing gear you would need. And a trailer. And a tow bar for your vehicle and all the tools to fit it.
Of course you would then go back and buy everything you need , tools and paints to respray your motorhome, ladders, planks and so on to stand on. You would of course need a decent generator to run the powerful compressor, both of which you can get in store.
Having parked up in their massive car park overnight you could spend the next day getting everything you need to carry out a major service.
These shops are in every town in Norway, you don't have to go looking for them. And their prices are excellent, cheaper than the DIY shops here.