The Pietta 1858 Remington is a pretty good gun out of the box, and we use them for N-SSA 25 and 50 yard competition, but most have to be accurized. Your alternative is an Old Army, which pretty much duplicates what you can do to an 1858 with over $1200 in alterations. Bill Ruger knew what he was doing.
A couple of tips:
Remove the cylinder between loadings and pull a Bore Snake through the barrel.
Buy a cylinder loading stand. This allows you to remove the cylinder from the gun and load it on a table separate from the gun.
Use Cream of Wheat on top of black powder to fill out remaining space under the bullet when using less than maximum loads. Each chamber should be tightly compressed with the bullet just under the chamber face.
NEVER EVER USE PYRODEX. This stuff is horribly corrosive, oily and difficult to get offf- which is really important in a cap & ball revolver. 3F black powder is the preferred propellant, but I would also consider Triple 7 powder (not pellets).
Use a good lube such as Lens Lube over the chamber mouth or use a Wonder Wad. You dont need 6 chambers going off simultaneously.
Clean with lots of HOT WATER. My wife just loves the smell of black powder going down the sink!
Use Ballistol for cleaning, lubrication and preservative. This stuff neutralizes black powder very well, has a pleasant smell and is pretty mild in comparison to some other products;. Home Depot now carries Ballistol- which I have never seen in a gun shop. I use it on all my black powder guns and have no rust whatsoever on them.