Your clarification means a lot -- "baked" potato in the U.S. tends to be a whole potato cooked on its own, where the insides become fluffy and creamy, and is done with larger starchy white potatoes, or sweet potatoes work well, too.
Roasted potatoes, on the other hand, tends to be (in the U.S.) be smaller "new" potatoes, waxy potatoes, or even larger starchy potatoes cut up (eg, 'oven fries').
The starchy potatoes only really hold up well when roasting if it's very high heat or a short amount of time -- if you're going to be cooking them with the roast as there's going to be moisture in there, I'd go for a waxy potato (eg, Red Bliss).
As for the browning -- probably coat them well with oil, and if they're not brown enough for your liking when you pull the roast, as you're going to have to rest it anyway, drain the meat juices, crank the oven up to somewhere around 450F (230C) and leave the potatoes in for a few extra minutes.
ps. yes, I know a sweet potato isn't a potato. And I also tend to use Yukon Gold for just about everything, as it makes great baked potatoes, and roasted potatoes (although, not sure how well with a roast at the same time) and they're good in pot roast and stews if you don't add them too early.
Best thing to do is to keep them out of the light in an cool dark dry place. I usually put them in a hessian bag to try and keep the moisture away.
Don't store them in the fridge or anywhere that gets direct sunlight.
Best Answer
It's actually pretty straight forward and fairly easy to do.
The moisture of a potato, will allow it to cook without burning. Just make sure you wrap them with no exposed areas, in order to trap the steam.