Answer: pilein

AnswerCrossword Clue
PILEIN

Board en masse

PILEIN

Enter all at once

PILEIN

Offer to a bunch of hitchhikers

PILEIN
Offer from a driver
PILEIN
Enter en masse
PILEINEnter as a group
PILEINScramble aboard
PILEINFill the SUV
PILEINBoard as a group
PILEINGo for a car-cramming record, say
PILEINOffer to a group of hitchhikers
PILEINEnter all together