I bought 4 round burgandy push lights at my local dollar store- $2 plus 8 AA
batteries.  Would've used velcro or twist ties to attach, but clear fishing
line was handy so I tied 'em to the small wood screws from which they hang.

1 by sliding door, 1 inside closet, 1 on right side of rear hatch, 1 extra.
Not fancy, but cheap & easy.     -P