I've heard that you have to take it down to every individual screw, but I can't see taking the frame apart. I've done it a few times actually, but I have owned BP revolvers for about 15 years and normally just clean the barrel/cylinder. I'd like to start carrying a BP revolver wich would meen shooting it every 2 weeks or so to put a fresh charge in it and it seems like to much work (more chance to lose/break/damage parts) to take the frame apart.

1. I remove the cylinder, lever and plunger, then clean the barrel/frame, cylinder and lever parts with hot soapy water and a toothbrush and bore brush.
2. I finish them off with a long hot tap water rinse - long enough to heat the metal up to the water temp.  
3. I dry them quickly with a towel to remove as much water as possible, then let the heat do the rest of the drying.
4. I squirt some CLP through a fine tipped oiler into the cylinder bolt, hand, trigger and hammer recesses to re-lube the interior parts.
5. I wipe down all the exterior metal with a lightly oiled cloth.  

I don't generally remove the grips each time I shoot it and I take care not to get them wet or let water weep under them.  But I do periodically take them off and clean and re-oil underneath them.

I've done the above process for about 30 years now and have never had rust issues on any of my cap and ball revolvers.

I depends on how much fouling is on it after a range session.
One or two cylinders only gets a quick break down and wipe.
60+ rounds get complete tear down, scrub, oven bake, oil bath, reassemble.

No need to take it down entirely.  That's a modern thing.  If the Civil War soldier tried it, he'd lose the parts in the field and have to pay for a new gun (or get one from the enemy).  

If you must do it, do it once a year and after you've baked something in the oven.  Toss it in and let it dry in the residual heat.

Agreed.  As noted above, I've been shooting and cleaning with out complete disassembly for 30 years now with no rust issues at all.

I have taken a cap and ball revolver apart to the individual parts level a time or two, for reasons other than cleaning (which if nothing else verified the insides looked fine) and it can be an involved process in some pistols with small parts and springs that can wander off.

Between a hot soapy water wash, hot water rinse, drying with a towel and then residual heat, and liberally re-oiling through the available holes and recesses, then wiping off the excess, the pistol will be just fine.

I've done that with this pistol, a Colt Signature Series 1847 Walker Colt, since the mid 1990s when I bought it, and it's still in great shape.  They sell for around $800, now, so obviously I have a great deal of confidence in this cleaning process:

This is almost exactly how I do it. I'll also use a Q-tip to clean around the hammer and on other movable parts on the frame. The only parts I clean by submerging and scrubbing in hot soapy water are the barrel assembly and cylinder. The frame gets a wipe down with a wet rag and then gets oiled up.

DakotaFAL Love your  Walker, I purchased the 1860 Army with fluted cylinder, could locate Walker anywhere, the 1860 was on backorder for a long time.
Fit and finish are outstanding on that series.

After a few cylinders, I find my '51 Navy has corrosive fouling blasted all through it.  I have to take it down, since the residue doesn't really rinse off completely, I find I have to physically wipe it off to get it all.

Depends on the gun.

Field strip (remove cylinder, nipples, reloading lever and rammer).

Detail cleaning should be once a year if you shoot it a lot.   Learn how (but a gunsmithing book) or take it to a gunsmith (more expensive in the long run).