I have a Single Speed 29er that I would like to rig up to ride for the Summer while I work at a Scout Camp. I am the Camp Director - and often travel the ~2mi road to visit, deliver items, etc. In the past I have walked or used a golf cart. I want to lose weight this Summer and plan to ride.

What items would you recommend for a few things:
1) Light to be able to ride the [camp] road at night - no other traffic, I just need to see where I am going
2) I have a rear rack - what would you recommend I use to carry items I need to deliver? (typically small)
3) Other thoughts?

4) Diet/Routine you would recommend to lose weight in the 6-8 weeks of Summer Camp. The food cooked at the camp is "typical" for teenagers burning lots of calories. I can do a salad two meals a day, etc.

My bike is a KHS Solo-One upgraded with disc brakes.

ANY words of wisdom would be great.