Hidden kill switch

Small Safe that is bolted to the frame

Stealth in looking poor/ nothing of value in van

Trash decoy=deterrent

Never sleep in a predictable area or on a schedule.

If something weird happens, even slighty, leave immidiatly

Sleep with your keys in reach

Sleep closer to the door than your SO. 

Cover all lines of visibility into the living cabin. Not the smallest peephole left uncovered. 

Lock everything (obviously)

Option for extra precaution: Home Door Alarms

Guns may be illegal & could land you in court or prison fast. But bear spray sure won't. (used as theory and for information only, I do not condone the use of bear spray)