If its the 5.4 you might think about 24 roller followers and 24 lash adjusters (which is what it has instead of rockers and lifters).
I can't find a way to replace the lash adjusters without removing the camshafts. It's still easier with the front cover off but maybe not as easy as you were thinking.
2004 F-150 XLT
New Body Style
5.4 3v 4WD Auto with Electronic Shift on the Fly