We just travelled Rwanda using your guidebook from earlier this year, and I have to say it was of utmost value to us, be it in terms of general information about the country, be it in specific tricks and tips. So thanks for this excellent piece!
As there are always things changing, here are two points which we thought we should bring to your attention.
1) Lake Ruhondo/Ruhondo Beach Resort (pp. 239/240): we went there with our car taking the route you describe. As you rightly point out, you need a 4×4 to get there…and it is a long trip! An alternative, and in fact a preferable one, as we have been told, is to park the car opposite Ruhondo Beach Resort, at the power station, and then give them a call to fetch you by boat. We have not been there, but we were told that the road on the other side of the lake is much better and in fact significantly shorter to the power station. Unfortunately, I did not record the name of the settlement, but according to Google Maps it is called Nkumba solidarity camp.
2) Muhanga/Where to stay (p. 133). We stayed at the Centre St. André in Kabgayi which is all good and fine. Getting some food when you are not part of one of the many religious groups frequenting this place can be a problem though. It eventually always worked out, but it can be a bit nerve-wracking until you know, especially when you have to work as I had to do (in Muhanga). Generally, we found it quite a challenge in Muhanga to find the right place to eat in the intermediate price range – either you go for a streetside place, or then to the Splendid & co. Not sure what one can do about it, but I thought I mention that to you.