If you're playing the version with ice queen realm then go get the quest to kill Haggar and spend some time hitting & eating frost giants in FGJC cave.
That should push your St to ~22, maybe more and with big punch and high regen, you should be fine against them.
You might also check out the greater vault there for a potentially nice artifact weapon or maybe bracers of war.
With 22+ strength and big punch, skele king shouldn't be a problem, assuming you have confusion resistance and decent willpower.
Also, gremlin cave is a nice place to quickly level up weapon marks to lvl ~7 or even 9, without running the risk of uber-gremlins.
"Hell is empty and all the devils are here."