Sounds fantastic, wish I were doing it. I've done a lot of this in a dodgy old Hilux, so you should have no problem on an Africa Twin.
If you stick to tourist places, you're main worry will be getting fuel and possibly even food. An alternative route would be to go up through Botswana (plenty of fuel and friendly people everywhere). There are several possiblities:
1) up through Botswana, cross into Zim at Kazangula/Kasane (i once saw a herd of buffalo cross _through_ that border post), then on to Vic Falls (watch out for thieves in the campsite) and into Zambia
2) if things got really bad in Zim, you can just go from Kasane to Zambia (used to be the Kazangula ferry, but i think they may have built a bridge now.
3) this is really cool - take the transit route through Chobe National Park to Ngoma Bridge, cross the Chobe into Namibia, then onto Katima Mullilo and into Zambia. The sandy road between the Botswana border post and KM might be rather exciting. The Transit Route is graded gravel. I think that they allow bikes through the Transit Route, but i'm not certain, as you will encounter BIG game. Camp at the Chobe Safari Lodge in Kasane - they will advise you of good routes etc - and don't miss their Fish Eagle boat safari.
I'd recomend giving Gaborone a miss though - unless you want to stay at Citi Camp next to the country's loudest bar. Perhaps cross the border into the Tuli Block or the Tswapong Hills, or to Serowe village. Nata Lodge near the Sua Pans complex is the usual place to stay on the way up to Chobe (nice bar, and they'll advise you of how to get a good view of the salt pans).
As the Batswana say - "Gosiame rra".
ps - you'll find the roads in Botswana to be quiet, but with enough vehicles so that someone will help if you break down. I think the longest stretch without fuel on the routes i mentioned is about 400 km, as the petrol station at Mpandamatenga, half way between Nata and Kasane is closed (don't qoute me on that, so take a small plastic can).
And remember, don't ride at night - hitting an elephant really hurts.
[This message has been edited by Roboyobo (edited 02 January 2003).]