I've taken the opportunity to smoke a couple picnics in the past 18 months or so. I removed the skin and bagged it for the freezer to use for fried skins (they turned out pretty good once I found the right methods, btw). Skin-off allows for better smoke reaction/penetration, as does a thin trimmed fat cap...fat cap helps protect the meat from temp spikes and self bastes the meat after it begins to render down, so I suggest to not get too carried away with the blade.
There are a few spots on the picnic (maybe only one) which has a stronger flavor than anywhere on the boston butt, IMO...seems like it comes from closer to the knee joint. Probably one of the darker colored small muscle bundles. Anyway, that's what I remember, but it's been about 8-9 months ago when I smoked my last picnic, and I've slept a few times since then, not to mention, had a few all-night smokes since that one, too.
The butt or picnic are both excellent choices for PP...I think I actually liked eating the picnic best...I used a pretty bold and intense dry rub on the last one as I recall, and it went well with a hickory/mesquite smoke and the heartier flavor of the picnic.
Tenderness will be accomplished the same as you would for a butt...low & slow @ 225-235* to an internal of 170-180*, and foil to 200* or better, then rest for a few hours wrapped in towels.
EDIT: Also, temp-hold method after foiling has helped me turn some lean/tough meat including brisket flat into pullable meat...figure about 30 minutes/lb @ 195-200* after reaching 180* I/T.
Man, just writing about this makes me want to smoke another...brings back some mighty fine memories!
One thing before I go, if you get a picnic over about 6 lbs, they can get stubburn when they hit the stall...lots of cartilage and connective tissue there with the joint...just so you're ready...trust your probes, and be sure to stick 'em right...not hitting or getting close to a bone can seem a bit tricky with the picnic..
Smoke one up for us and give us your take...I think you'll like the way it pulls and the flavor is a nice twist when you get it all tossed together...oh, try to catch the drippings to use for a natural finishing sauce if you can...even the foil liquids would be great.
Enjoy, brother!
Eric