I think going on an African Safari is grounds for suspending running for one week. You can make future gains when you return.

Just have fun. If you can find a treadmill, great. If not, don't sweat it. You have a lifetime to run.

Runners can be so obsessive that we forget to enjoy things like AFRICAN SAFARIS! I doubt any long time runner would fret over missing one week for that experience, so you shouldn't, either.

Next time, you theoretically could plan your vacation around your training (find a hotel with a treadmill, at least, if not design your whole vacation around fitness, as I have often done), which is also fun. But sometimes life is just telling you to sit back and relax.

Spicegeek hit the nail right on the head.  Jump ropes for cardio and tubing/bands for resistence training.  Don't panic if the first couple of bouts with the jump rope don't go as planned.  Getting the rhythm takes a while so there are a lot of starts and stops.  You can do jumping jacks instead...no rope and you'd be amazed how cardio vascular that is.  You could also do some speed work , 50 meter sprints between the tent and the facilities.  Finally, you won't lose everything in 3 weeks.  It will come back surprisingly quickly.  Just don't plan a race the week you come home.  Think of that vacation as a "recovery" after a long race and begin to build again when you come home.  Cut back 10 - 20% from your regular distance and speed and gradually pick it up.  You may discover that the lay off both mental and physical gave you a boost.  By the way, post a picture when you come back.  Most of us will never get to do something that great.