I used to drive out a lot in the 4Runner a decade ago, off of JP, WB etc
always brought along a "come-along" (hand winch) and a home-made Ice Anchor to handle crack troubles
2"x2"x 30"L iron angle + 1/2" eyebolt ( one in the pic was opened after a heavy pull, better use welded/casted ones )
the end rope is for pulling the anchor back up from the hole