Well duh, I'll have 12vdc running all over the tunnel and there are no shortage of small 12vdc incandescent bulbs from the auto parts store. A taillight bulb on each side of every truss frame about 8-10 foot up would do it.
I use a dozen or so of the El cheapo dollar store solar lights you just stick in the ground. I only use them up on our patio where all our container gardening is done. They seem to keep away the raccoons. Most will last longer than one summer. Then I put them in the garage for the winter. It’s a good solution for me.