Happy to help where we can, SD - please feel free to reach out if you think I can be of any assistance.
In terms of location pointers, while I have hunted extensively over all of SA, my home province is Natal (I was born and raised in Zululand) so can give very detailed
advice opinions on that province, if of value. Happy to comment where I can on other areas but there are likely more qualified members on the site.
To be frank, I think your idea about Zim is a good one - I would be very tempted to consider Zim given your criteria and outline. If you plan to be broadly self sufficient, then quality of utility services and the like are not a serious consideration. If air travel is a routine option, then the quality of roads also drops down the worry-list. At a people level, I think Zimbabwean workers are a great proposition. Security in Zim seems a lot better generally. Of course the security of land tenure is a the MAJOR stumbling block and deal breaker.
Regarding distances that hunters are willing to travel, I would not be too concerned on this point (unless you're desperate to have them crowding through the gates, which I am sure is the opposite of your objective!). Sure you're not going to get a weekend meat hunter who's going to drive for 8 hours to shoot 2 impala ewes. But for decent hunting in a properly run, unspoilt environment, there is always a market and they will be prepared to travel.
To give some context (and I will generalize grossly here) within 2 hrs drive of Jhb, the majority of game farms cater to the weekend warrior hunter segment. Usually with fancier accommodation and all the modcons - as one might reasonably expect a consumer group that is more affluent and time-strapped would want, including proximity to the city. Of course they pay for the privilege of venues that cater to their wishes. Corporate and big group hunts are big constituent of this segment and the venues are set up accordingly. They want the bar fridge to be bigger than the cold room and their animals to morph from the back of the vehicle into vacuum packed packages.
The huge majority of this market is not prepared to drive 5 hours to a remote destination and have to hunt hard on foot, tolerate more humble amenities etc and quite possibly go home empty handed or with only an animal or 2.
Of course the more committed hunter segment often really aspires to a scenario like my last sentence. And if the maximization of the commercial side is not a primary driver, then you can really target this segment (I'm boldly presuming that this would more likely be your preferred crowd). What I have experienced with some of my own hunting destinations is that the operators tend to focus on repeat/returning hunters and generally keep their animal prices down, not that we have ever discussed or negotiated this. Their explanation was that they value hunters of known capability who hunt responsibly, shoot enough animals to make it worth their (the game farmer's) while, and they're happy to incentivise us to return annually by giving us a good deal - they recognize that they're 500 miles from the major cities and thus too far for casual hunters to be their target market. We value the peace and unspoilt landscape and basic accommodation they offer, on top of the hunting, and see huge value in making the trip - win win!
I'm rather belabouring my point but I think you will have no problem finding the type and numbers of hunters you wish by a bit of basic tailoring of your hunting proposition.
As you stated your wish to be as far from people as possible, then the Karoo may well be an appealing location. It's very 'big country' with a low carrying capacity, so game farms tend to be very extensive and land prices per acre/hectare are very low. It is an arid region so water supply is a big consideration. But human population density is extremely low and security is thus much better - and the generally harsh environment makes it unappealing were there ever to be a land-grab.
Counting against it would be the low carrying capacity and relatively limited game variety endemic to the region. Yes you could introduce other species if there is sufficient water and food but I suspect that this might go against the grain.
Game type and variety might be another criterion to add to your filter when shortlisting locations.
