scale of 1-5, pipeline will range all over....if you avoid the bottomless mud, a solid 2-3...I've run most of it with 31" tires on an opendiffed minitruck with no problems, just watch for the DEEP stuff. Honestly, unless you like the mud and a rare 12" rock, the pipeline isn't much...
MUCH better wheelin at McCaslin Mountain tho....Lakewood WI, take Cnty F east for 10 miles. Lots of trails to wander thru back there, including some rock gardens I opened a couple years back.
I would not do either without someone along that knows the trails....the Pipeline has some closed off areas, and the FS is not shy about fines. McCaslin can get confusing, with it's intertwined trails and occasional DEEP spots.
Pipeline can be access easiest from the S side....from Mountain WI, take Cnty W east for 10-ish miles, then head north once you see it. "Generic" maps available at McCaslin as well, and at the FS office in Lakewood.
Again, avoid the deep holes....some will swallow 44" swampers AND the bed of the 12" lifted truck running them....
Fawker 
