If you're carrying a shit ton of expendable stuff that's eating up weight, you can always find magicians and shamans and ask them for summoned bags. 0.1 weight, 100% reduction.
http://wiki.project1999.org/Dimensional_Hole_(Item)
http://wiki.project1999.org/Spirit_Pouch_(Item)
Tink bags are also obvious solutions. Just PL someone for 2-3 hours and you'll have your 5k.