Step 1: Season the Beast
Unroll some wax paper and plop the roast on to it. Don't be afraid to season it a lot. Some ideas might be to stuff some garlic inside some holes in the roast or just to rub some spice into it.
Step 2: Start Wrapping
OK so let me preface this by the fact that you will be wrapping a lot of wax paper over this roast. Don't be stingy with it as it's going to protect your roast from nature. I don't have an exact amount of rolling that I do, I just kind of judge when it's thick enough.
I start by tightly rolling it in one direction, and I tuck in the ends of the paper to create a packet. After rolling this with about 6-7 layers of wax paper I cut the paper and rotate the roast and roll it end over end a few times. I tuck in the sides while doing that. I finish off the roast by rolling it another 6-7 times in the original direction, again tucking in the ends as I go.
In the end you should have a nice compact rolled roast.
Step 3: Truss Me Around This
You will want to truss your roast, this step will keep it from falling apart over the fire.
Make sure you secure the open ends so that they can remain closed. It doesn't have to be a fancy job, just make sure it's thorough.
Now if you go camping for a while (I usually go for 10 day stretches) I suggest that you freeze the roast (in a Ziploc bag) and use it as additional ice for your cooler. As a result I usually serve this meal around day 3-4, basically once it's thawed out. If you try cooking this puppy before it's thawed, then you are on your own for the results, I can't guarantee the cooked to perfection!
This year I will be trying wrapping my roast on the outside with some newspaper to see if it will remain frozen longer. If you try this, remove the newspaper before cooking. (edit: the newspaper helped a great deal with keeping things cold)
Step 4: Prepare the Fire
Ok so you want a good fire that has been burning for a while so that there are some hot coals. If you are impatient, you are welcome to toss some charcoal into the fire, however don't use any that has chemicals on it, just plain old charcoal.
I prefer regular coals myself so I stoke a good fire first.
Push the coals around to create a nice warm bed for your packet. The fire will continue to burn on one side of the fire pit, but you want most of the heat to come from the coals.
Step 5: Place the Packet on the Coals and Wait
Place the packet on the coals. Don't be alarmed when the paper starts to burn, that's why you put many layers. Start your timer, or start counting steamboats but you want to wait 15 minutes before rotating the roast. (For those who care, that's 900 steamboats) never mind the foil wrapped sweet potato there on the left.
In terms of rotating, we are considering this packet as having 4 sides. Each side will be cooked for 15 minutes on the coals. When the 15 minutes are up carefully rotate the roast 90 degrees in one direction to place the next side on the coals. At the end it should look a lot like the final picture in this set.
If you don't like your roast done medium rare, go to the final step to find out about cooking times.
Step 6: Once You've Rotated 4 Times (cooked All Sides)
After an hour you should have cooked 4 sides for 15 minutes each. Carefully remove the roast from the fire and place it on a tray/plate/whatever you've got. Peel the paper back gently and allow the roast to sit for 10 minutes (this will allow the juices to remain inside) You will have to pick off some of the paper left over on the roast while you wait. The first picture has some of the paper on the right and some left to remove.
After the roast is well rested, cut and serve. You should have a beautiful medium rare roast at your disposition.
Step 7: Some Things to Consider...
I like my roast medium rare... If you want to cook it longer go right ahead, however I suggest adding the same amount of time to each side in order to give a consistent heat all around. (ie: 18 minutes on each side) I don't know exactly how long to cook for other levels of "done-ness", so if anyone experiments with this, let me know and I will add the times here. People can also cook their individual slice over the flames a little longer if there are people with different preferences.
Funkpol made it!