Does your van have the 4 bladed prop? That will do a huge amount in reducing the amount of crap picked up by it.
I wouldn't stress yourself too much on the rubber mudflaps. Usually it is just a bit of mud and little small stones that are thrown up by the main gear. Not enough to cause damage. The biggest damage comes from the larger rocks that your prop will pick up.
Just be conscious of where you are taxiing, and how much power you are using. Although I'm not sure how much control you have over that with the Garret engine.
One of the biggest annoyances I had with my first officers when taxiing the van was their ability to keep it moving.
Once moving, it takes very little power to keep it moving. Take the turns as widely as possible, lead it with a bit of power and only use the brake to get the nose wheel around sharper. Roughly 30 degrees before where you want to be pointing, start straightening the nose wheel out. It will keep the van moving and won't bog down. If you are heavy and not have the nose wheel centered, it will take a lot of power to get it straight again... and thats where most of the stone chips come from.
With that 900hp mod, you would be very wise to avoid the dust as much as you can. Always do your turns on the dusty runways into wind so the dust is blown away from you and not sucked into the engine when you turn into your own dust cloud.
You won't have any protection from birds being ingested, which there is a lot of in Africa.
And I don't think ice is going to be much of a problem in VFR ops in South Sudan.
Probably would have been better off getting a Blackhawk converted van, or an EX. With the payload extender as well. Bumps it up to just over 9000lbs.