I hear the 6.0 gets lazy if you let it sit too much. I have a work car and we drive the wifes car for most errands so its not uncommon to go 5 or 6 days inbetween driving the truck. What seems to be considered a long time to let it sit? Should I take it into town during the week a couple times?
Just drive it like you stole it when you do drive it. I do the same sometimes 7-8 days before I take truck. I do especially in winter plug it in with an automatic battery tender. I will say my voltage stays higher than when I never left it plugged in.
I have left my truck sit for over a month and it fired right up first try and drove fine. There isn't anything wrong with them sitting. Just drive it spiritedly after it fully warms up for a few miles and your good to go.
Actually sitting for a long period in a humid environment often ends with a rusty unison ring in the turbo. A couple weeks at a time is no big deal. Just be sure to get it fully warmed up when you drive it and give the turbo some full boost exercise on a regular basis.